diff --git a/python/python-psi-impl/src/com/jetbrains/python/codeInsight/intentions/PyQuotedStringIntention.java b/python/python-psi-impl/src/com/jetbrains/python/codeInsight/intentions/PyQuotedStringIntention.java
index 4bc7621b2367..6d7894b6e25e 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/codeInsight/intentions/PyQuotedStringIntention.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/codeInsight/intentions/PyQuotedStringIntention.java
@@ -3,18 +3,26 @@ package com.jetbrains.python.codeInsight.intentions;
 
 import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
+import com.intellij.psi.SmartPointerManager;
+import com.intellij.psi.SmartPsiElementPointer;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.IncorrectOperationException;
+import com.intellij.util.containers.ContainerUtil;
 import com.jetbrains.python.PyPsiBundle;
 import com.jetbrains.python.psi.*;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import static com.jetbrains.python.psi.PyUtil.as;
 
 /**
  * User: catherine
  * Intention to convert between single-quoted and double-quoted strings
  */
 public class PyQuotedStringIntention extends PyBaseIntentionAction {
+  private SmartPsiElementPointer<PsiElement> myConversionTarget;
 
   @Override
   @NotNull
@@ -28,54 +36,58 @@ public class PyQuotedStringIntention extends PyBaseIntentionAction {
       return false;
     }
 
-    PyStringLiteralExpression string = PsiTreeUtil.getParentOfType(file.findElementAt(editor.getCaretModel().getOffset()), PyStringLiteralExpression.class);
-    if (string != null) {
-      final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(string, PyDocStringOwner.class);
-      if (docStringOwner != null) {
-        if (docStringOwner.getDocStringExpression() == string) return false;
-      }
-      String stringText = string.getText();
-      int prefixLength = PyStringLiteralUtil.getPrefixLength(stringText);
-      stringText = stringText.substring(prefixLength);
+    PyStringElement stringElement = findConvertibleStringElementUnderCaret(editor, file);
+    if (stringElement == null) return false;
+    PyStringLiteralExpression stringLiteral = as(stringElement.getParent(), PyStringLiteralExpression.class);
+    if (stringLiteral == null) return false;
 
-      if (stringText.length() >= 6) {
-        if (stringText.startsWith("'''") && stringText.endsWith("'''") ||
-              stringText.startsWith("\"\"\"") && stringText.endsWith("\"\"\"")) return false;
-      }
-      if (stringText.length() > 2) {
-        if (stringText.startsWith("'") && stringText.endsWith("'")) {
-          setText(PyPsiBundle.message("INTN.quoted.string.single.to.double"));
-          return true;
-        }
-        if (stringText.startsWith("\"") && stringText.endsWith("\"")) {
-          setText(PyPsiBundle.message("INTN.quoted.string.double.to.single"));
-          return true;
-        }
-      }
+    final PyDocStringOwner docStringOwner = PsiTreeUtil.getParentOfType(stringLiteral, PyDocStringOwner.class);
+    if (docStringOwner != null && docStringOwner.getDocStringExpression() == stringLiteral) return false;
+
+    String currentQuote = stringElement.getQuote();
+    boolean allComponentsCanBeConverted = ContainerUtil.all(stringLiteral.getStringElements(),
+                                                            s -> s.getQuote().equals(currentQuote) && canBeConverted(s));
+
+    myConversionTarget = SmartPointerManager.createPointer(allComponentsCanBeConverted ? stringLiteral : stringElement);
+
+    if (currentQuote.equals("'")) {
+      setText(PyPsiBundle.message("INTN.quoted.string.single.to.double"));
     }
-    return false;
+    else {
+      setText(PyPsiBundle.message("INTN.quoted.string.double.to.single"));
+    }
+    return true;
+  }
+
+  public @Nullable PyStringElement findConvertibleStringElementUnderCaret(@NotNull Editor editor, @NotNull PsiFile file) {
+    PsiElement elemUnderCaret = file.findElementAt(editor.getCaretModel().getOffset());
+    PyStringElement stringElement = PsiTreeUtil.getParentOfType(elemUnderCaret, PyStringElement.class, false);
+    return stringElement != null && canBeConverted(stringElement) ? stringElement : null;
+  }
+
+  public boolean canBeConverted(@NotNull PyStringElement stringElement) {
+    return !stringElement.isTripleQuoted() && stringElement.isTerminated() && !stringElement.getContentRange().isEmpty();
   }
 
   @Override
   public void doInvoke(@NotNull Project project, Editor editor, PsiFile file) throws IncorrectOperationException {
-    PyStringLiteralExpression string = PsiTreeUtil.getParentOfType(file.findElementAt(editor.getCaretModel().getOffset()), PyStringLiteralExpression.class);
-    PyElementGenerator elementGenerator = PyElementGenerator.getInstance(project);
-    if (string != null) {
-      final String stringText = string.getText();
-      int prefixLength = PyStringLiteralUtil.getPrefixLength(stringText);
-      final String text = stringText.substring(prefixLength);
-
-      if (text.startsWith("'") && text.endsWith("'")) {
-        String result = convertSingleToDoubleQuoted(stringText);
-        PyStringLiteralExpression st = elementGenerator.createStringLiteralAlreadyEscaped(result);
-        string.replace(st);
-      }
-      if (text.startsWith("\"") && text.endsWith("\"")) {
-        String result = convertDoubleToSingleQuoted(stringText);
-        PyStringLiteralExpression st = elementGenerator.createStringLiteralAlreadyEscaped(result);
-        string.replace(st);
-      }
+    @Nullable PsiElement target = myConversionTarget.getElement();
+    if (target instanceof PyStringLiteralExpression) {
+      ((PyStringLiteralExpression)target).getStringElements().forEach(this::convertStringElement);
     }
+    else if (target instanceof PyStringElement) {
+      convertStringElement((PyStringElement)target);
+    }
+  }
+
+  public void convertStringElement(@NotNull PyStringElement stringElement) {
+    Project project = stringElement.getProject();
+    String result = stringElement.getQuote().equals("'")
+                    ? convertSingleToDoubleQuoted(stringElement.getText())
+                    : convertDoubleToSingleQuoted(stringElement.getText());
+    PyElementGenerator elementGenerator = PyElementGenerator.getInstance(project);
+    PyStringLiteralExpression st = elementGenerator.createStringLiteralAlreadyEscaped(result);
+    stringElement.replace(st.getFirstChild());
   }
 
   private static String convertDoubleToSingleQuoted(String stringText) {
@@ -95,9 +107,9 @@ public class PyQuotedStringIntention extends PyBaseIntentionAction {
       else if (ch == '\'') {
         stringBuilder.append("\\'");
       }
-      else if (ch == '\\' && charArr[i+1] == '\"' && !(i+2 == charArr.length)) {
+      else if (ch == '\\' && charArr[i + 1] == '\"' && !(i + 2 == charArr.length)) {
         skipNext = true;
-        stringBuilder.append(charArr[i+1]);
+        stringBuilder.append(charArr[i + 1]);
       }
       else {
         stringBuilder.append(ch);
@@ -123,9 +135,9 @@ public class PyQuotedStringIntention extends PyBaseIntentionAction {
       else if (ch == '"') {
         stringBuilder.append("\\\"");
       }
-      else if (ch == '\\' && charArr[i+1] == '\'' && !(i+2 == charArr.length)) {
+      else if (ch == '\\' && charArr[i + 1] == '\'' && !(i + 2 == charArr.length)) {
         skipNext = true;
-        stringBuilder.append(charArr[i+1]);
+        stringBuilder.append(charArr[i + 1]);
       }
       else {
         stringBuilder.append(ch);
diff --git a/python/testData/intentions/convertingQuotesOfGluedStringWithDifferentElementQuotes.py b/python/testData/intentions/convertingQuotesOfGluedStringWithDifferentElementQuotes.py
new file mode 100644
index 000000000000..5f17ebdb0c90
--- /dev/null
+++ b/python/testData/intentions/convertingQuotesOfGluedStringWithDifferentElementQuotes.py
@@ -0,0 +1,3 @@
+s = ('f<caret>oo'
+     "bar"
+     'baz')
diff --git a/python/testData/intentions/convertingQuotesOfGluedStringWithDifferentElementQuotes_after.py b/python/testData/intentions/convertingQuotesOfGluedStringWithDifferentElementQuotes_after.py
new file mode 100644
index 000000000000..3c9164576b95
--- /dev/null
+++ b/python/testData/intentions/convertingQuotesOfGluedStringWithDifferentElementQuotes_after.py
@@ -0,0 +1,3 @@
+s = ("foo"
+     "bar"
+     'baz')
diff --git a/python/testSrc/com/jetbrains/python/intentions/PyIntentionTest.java b/python/testSrc/com/jetbrains/python/intentions/PyIntentionTest.java
index 4ed66d9aa36b..bf5cec0a23af 100644
--- a/python/testSrc/com/jetbrains/python/intentions/PyIntentionTest.java
+++ b/python/testSrc/com/jetbrains/python/intentions/PyIntentionTest.java
@@ -206,6 +206,11 @@ public class PyIntentionTest extends PyTestCase {
     doTest(PyPsiBundle.message("INTN.quoted.string.double.to.single"));
   }
 
+  // PY-15608
+  public void testConvertingQuotesOfGluedStringWithDifferentElementQuotes() {
+    doTest(PyPsiBundle.message("INTN.quoted.string.single.to.double"));
+  }
+
   public void testConvertLambdaToFunction() {
     doTest(PyPsiBundle.message("INTN.convert.lambda.to.function"));
   }