diff --git a/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java b/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java
index dc5f528442d9..f1a7b8706a14 100644
--- a/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java
+++ b/RegExpSupport/src/org/intellij/lang/regexp/validation/RegExpAnnotator.java
@@ -21,6 +21,7 @@ import com.intellij.lang.ASTNode;
 import com.intellij.lang.annotation.Annotation;
 import com.intellij.lang.annotation.AnnotationHolder;
 import com.intellij.lang.annotation.Annotator;
+import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.PsiComment;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -37,6 +38,7 @@ import java.util.Set;
 public final class RegExpAnnotator extends RegExpElementVisitor implements Annotator {
   private static final Set<String> POSIX_CHARACTER_CLASSES = ContainerUtil.newHashSet(
     "alnum", "alpha", "ascii", "blank", "cntrl", "digit", "graph", "lower", "print", "punct", "space", "upper", "word", "xdigit");
+  private static final String ILLEGAL_CHARACTER_RANGE_TO_FROM = "Illegal character range (to < from)";
   private AnnotationHolder myHolder;
   private final RegExpLanguageHosts myLanguageHosts;
 
@@ -65,7 +67,8 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
       final Character f = ((RegExpChar)from).getValue();
       if (t != null && f != null) {
         if (t < f) {
-          myHolder.createErrorAnnotation(range, "Illegal character range (to < from)");
+          if (handleSurrogates(range, f, t)) return;
+          myHolder.createErrorAnnotation(range, ILLEGAL_CHARACTER_RANGE_TO_FROM);
         }
         else if (t == f) {
           myHolder.createWarningAnnotation(range, "Redundant character range");
@@ -80,6 +83,30 @@ public final class RegExpAnnotator extends RegExpElementVisitor implements Annot
     }
   }
 
+  private boolean handleSurrogates(RegExpCharRange range, Character f, Character t) {
+    // \ud800\udc00-\udbff\udfff
+    PsiElement prevSibling = range.getPrevSibling();
+    PsiElement nextSibling = range.getNextSibling();
+
+    if (prevSibling instanceof RegExpChar && nextSibling instanceof RegExpChar) {
+      Character prevSiblingValue = ((RegExpChar)prevSibling).getValue();
+      Character nextSiblingValue = ((RegExpChar)nextSibling).getValue();
+
+      if (prevSiblingValue != null && nextSiblingValue != null) {
+        if (Character.isSurrogatePair(prevSiblingValue, f) && Character.isSurrogatePair(t, nextSiblingValue)) {
+          if (Character.toCodePoint(prevSiblingValue, f) > Character.toCodePoint(t, nextSiblingValue)) {
+            TextRange prevSiblingRange = prevSibling.getTextRange();
+            TextRange nextSiblingRange = nextSibling.getTextRange();
+            TextRange errorRange = new TextRange(prevSiblingRange.getStartOffset(), nextSiblingRange.getEndOffset());
+            myHolder.createErrorAnnotation(errorRange, ILLEGAL_CHARACTER_RANGE_TO_FROM);
+          }
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
   @Override
   public void visitRegExpClass(RegExpClass regExpClass) {
     final HashSet<Character> seen = new HashSet<Character>();
diff --git a/RegExpSupport/testData/RETest.xml b/RegExpSupport/testData/RETest.xml
index d3d46032a3e0..ed30d45065b2 100644
--- a/RegExpSupport/testData/RETest.xml
+++ b/RegExpSupport/testData/RETest.xml
@@ -619,6 +619,22 @@
       <pattern>[\x4a-\x3f]</pattern>
       <expected>ERR</expected>
     </test>
+    <test>
+      <pattern><![CDATA[[<error descr="Illegal character range (to < from)">\udbff\udfff-\ud800\udc00</error>]]]></pattern>
+      <expected>OK</expected>
+    </test>
+    <test>
+      <pattern>[\ud800\udc00-\udbff\udfff]</pattern>
+      <expected>OK</expected>
+    </test>
+    <test>
+      <pattern><![CDATA[[<error descr="Illegal character range (to < from)">z-a</error>]]]></pattern>
+      <expected>OK</expected>
+    </test>
+    <test>
+      <pattern>[a-z]</pattern>
+      <expected>OK</expected>
+    </test>
     <test>
       <pattern>a\Qabc?*+.))]][]\Eb</pattern>
       <expected>OK</expected>