diff --git a/python/src/com/jetbrains/python/inspections/PyStringFormatParser.java b/python/src/com/jetbrains/python/inspections/PyStringFormatParser.java
new file mode 100644
index 000000000000..d1e52a14e9ae
--- /dev/null
+++ b/python/src/com/jetbrains/python/inspections/PyStringFormatParser.java
@@ -0,0 +1,179 @@
+package com.jetbrains.python.inspections;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author yole
+ */
+public class PyStringFormatParser {
+  public static abstract class FormatStringChunk {
+    private final int myStartIndex;
+    protected int myEndIndex;
+
+    public FormatStringChunk(int startIndex, int endIndex) {
+      myStartIndex = startIndex;
+      myEndIndex = endIndex;
+    }
+
+    public int getStartIndex() {
+      return myStartIndex;
+    }
+
+    public int getEndIndex() {
+      return myEndIndex;
+    }
+  }
+
+  public static class ConstantChunk extends FormatStringChunk {
+
+    public ConstantChunk(int startIndex, int endIndex) {
+      super(startIndex, endIndex);
+    }
+  }
+
+  public static class SubstitutionChunk extends FormatStringChunk {
+    private String myMappingKey;
+    private String myConversionFlags;
+    private String myWidth;
+    private String myPrecision;
+    private char myLengthModifier;
+    private char myConversionType;
+
+    public SubstitutionChunk(int startIndex) {
+      super(startIndex, startIndex);
+    }
+
+    public void setEndIndex(int endIndex) {
+      myEndIndex = endIndex;
+    }
+
+    public char getConversionType() {
+      return myConversionType;
+    }
+
+    public void setConversionType(char conversionType) {
+      myConversionType = conversionType;
+    }
+
+    public String getMappingKey() {
+      return myMappingKey;
+    }
+
+    public void setMappingKey(String mappingKey) {
+      myMappingKey = mappingKey;
+    }
+
+    public String getConversionFlags() {
+      return myConversionFlags;
+    }
+
+    public void setConversionFlags(String conversionFlags) {
+      myConversionFlags = conversionFlags;
+    }
+
+    public String getWidth() {
+      return myWidth;
+    }
+
+    public void setWidth(String width) {
+      myWidth = width;
+    }
+
+    public String getPrecision() {
+      return myPrecision;
+    }
+
+    public void setPrecision(String precision) {
+      myPrecision = precision;
+    }
+
+    public char getLengthModifier() {
+      return myLengthModifier;
+    }
+
+    public void setLengthModifier(char lengthModifier) {
+      myLengthModifier = lengthModifier;
+    }
+  }
+
+  private final String myLiteral;
+  private final List<FormatStringChunk> myResult = new ArrayList<FormatStringChunk>();
+  private int myPos;
+
+  private static final String CONVERSION_FLAGS = "#0- +";
+  private static final String DIGITS_OR_ASTERISK = "0123456789*";
+  private static final String LENGTH_MODIFIERS = "hlL*";
+
+  public PyStringFormatParser(String literal) {
+    myLiteral = literal;
+  }
+
+  public List<FormatStringChunk> parse() {
+    myPos = 0;
+    while(myPos < myLiteral.length()) {
+      int next = myLiteral.indexOf('%', myPos);
+      while(next >= 0 && next < myLiteral.length()-1 && myLiteral.charAt(next+1) == '%') {
+        next = myLiteral.indexOf('%', next+2);
+      }
+      if (next < 0) break;
+      if (next > myPos) {
+        myResult.add(new ConstantChunk(myPos, next));
+      }
+      myPos = next;
+      parseSubstitution();
+    }
+    if (myPos < myLiteral.length()) {
+      myResult.add(new ConstantChunk(myPos, myLiteral.length()));
+    }
+    return myResult;
+  }
+
+  private void parseSubstitution() {
+    assert myLiteral.charAt(myPos) == '%';
+    SubstitutionChunk chunk = new SubstitutionChunk(myPos);
+    myResult.add(chunk);
+    myPos++;
+    if (myPos < myLiteral.length() && myLiteral.charAt(myPos) == '(') {
+      int mappingEnd = myLiteral.indexOf(')', myPos+1);
+      if (mappingEnd < 0) {
+        chunk.setEndIndex(myLiteral.length());
+        myPos = myLiteral.length();
+        return;
+      }
+      chunk.setMappingKey(myLiteral.substring(myPos+1, mappingEnd));
+      myPos = mappingEnd+1;
+    }
+    chunk.setConversionFlags(parseWhileCharacterInSet(CONVERSION_FLAGS));
+    chunk.setWidth(parseWhileCharacterInSet(DIGITS_OR_ASTERISK));
+    if (myPos < myLiteral.length() && myLiteral.charAt(myPos) == '.') {
+      myPos++;
+      chunk.setPrecision(parseWhileCharacterInSet(DIGITS_OR_ASTERISK));
+    }
+    if (myPos < myLiteral.length() && LENGTH_MODIFIERS.indexOf(myLiteral.charAt(myPos)) >= 0) {
+      chunk.setLengthModifier(myLiteral.charAt(myPos));
+      myPos++;
+    }
+    chunk.setConversionType(myLiteral.charAt(myPos));
+    myPos++;
+    chunk.setEndIndex(myPos);
+  }
+
+  private String parseWhileCharacterInSet(final String characterSet) {
+    int flagStart = myPos;
+    while(myPos < myLiteral.length() && characterSet.indexOf(myLiteral.charAt(myPos)) >= 0) {
+      myPos++;
+    }
+    return myLiteral.substring(flagStart, myPos);
+  }
+
+  public List<SubstitutionChunk> parseSubstitutions() {
+    List<SubstitutionChunk> result = new ArrayList<SubstitutionChunk>();
+    for (FormatStringChunk chunk : parse()) {
+      if (chunk instanceof SubstitutionChunk) {
+        result.add((SubstitutionChunk) chunk);
+      }
+    }
+    return result;
+  }
+}
diff --git a/python/testSrc/com/jetbrains/python/PyStringFormatParserTest.java b/python/testSrc/com/jetbrains/python/PyStringFormatParserTest.java
new file mode 100644
index 000000000000..33f306b684fb
--- /dev/null
+++ b/python/testSrc/com/jetbrains/python/PyStringFormatParserTest.java
@@ -0,0 +1,80 @@
+package com.jetbrains.python;
+
+import com.jetbrains.python.inspections.PyStringFormatParser;
+import junit.framework.TestCase;
+
+import java.util.List;
+
+/**
+ * @author yole
+ */
+public class PyStringFormatParserTest extends TestCase {
+  public void testSimple() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("abc").parse();
+    assertEquals(1, chunks.size());
+    assertConstant(chunks.get(0), 0, 3);
+  }
+
+  private static void assertConstant(PyStringFormatParser.FormatStringChunk aChunk, final int start, final int end) {
+    PyStringFormatParser.ConstantChunk chunk = (PyStringFormatParser.ConstantChunk) aChunk;
+    assertEquals(start, chunk.getStartIndex());
+    assertEquals(end, chunk.getEndIndex());
+  }
+
+  public void testDoublePercent() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("abc%%def").parse();
+    assertEquals(1, chunks.size());
+    assertConstant(chunks.get(0), 0, 8);
+  }
+
+  public void testFormat() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("%s").parse();
+    assertEquals(1, chunks.size());
+    PyStringFormatParser.SubstitutionChunk chunk = (PyStringFormatParser.SubstitutionChunk) chunks.get(0);
+    assertEquals(0, chunk.getStartIndex());
+    assertEquals(2, chunk.getEndIndex());
+    assertEquals('s', chunk.getConversionType());
+  }
+
+  public void testSubstitutionAfterFormat() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("Hello, %s").parse();
+    assertEquals(2, chunks.size());
+    assertConstant(chunks.get(0), 0, 7);
+  }
+
+  public void testMappingKey() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("%(language)s").parse();
+    assertEquals(1, chunks.size());
+    PyStringFormatParser.SubstitutionChunk chunk = (PyStringFormatParser.SubstitutionChunk) chunks.get(0);
+    assertEquals("language", chunk.getMappingKey());
+    assertEquals('s', chunk.getConversionType());
+  }
+
+  public void testConversionFlags() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("%#0d").parse();
+    assertEquals(1, chunks.size());
+    PyStringFormatParser.SubstitutionChunk chunk = (PyStringFormatParser.SubstitutionChunk) chunks.get(0);
+    assertEquals("#0", chunk.getConversionFlags());
+  }
+
+  public void testWidth() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("%345d").parse();
+    assertEquals(1, chunks.size());
+    PyStringFormatParser.SubstitutionChunk chunk = (PyStringFormatParser.SubstitutionChunk) chunks.get(0);
+    assertEquals("345", chunk.getWidth());
+  }
+
+  public void testPrecision() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("%.2d").parse();
+    assertEquals(1, chunks.size());
+    PyStringFormatParser.SubstitutionChunk chunk = (PyStringFormatParser.SubstitutionChunk) chunks.get(0);
+    assertEquals("2", chunk.getPrecision());
+  }
+
+  public void testLengthModifier() {
+    List<PyStringFormatParser.FormatStringChunk> chunks = new PyStringFormatParser("%ld").parse();
+    assertEquals(1, chunks.size());
+    PyStringFormatParser.SubstitutionChunk chunk = (PyStringFormatParser.SubstitutionChunk) chunks.get(0);
+    assertEquals('l', chunk.getLengthModifier());
+  }
+}
diff --git a/python/testSrc/com/jetbrains/python/PythonAllTestsSuite.java b/python/testSrc/com/jetbrains/python/PythonAllTestsSuite.java
index a8b620f726d0..257c1b8d03b7 100644
--- a/python/testSrc/com/jetbrains/python/PythonAllTestsSuite.java
+++ b/python/testSrc/com/jetbrains/python/PythonAllTestsSuite.java
@@ -17,6 +17,7 @@ public class PythonAllTestsSuite {
   public static final Class[] tests = {
     PythonLexerTest.class,
     PyStringLiteralLexerTest.class,
+    PyStringFormatParserTest.class,
     PyEncodingTest.class,
     PythonParsingTest.class,
     PyStringLiteralTest.class,