diff --git a/java/java-tests/testData/codeInsight/completion/normal/LowercaseDoesNotMatchUnderscore.java b/java/java-tests/testData/codeInsight/completion/normal/LowercaseDoesNotMatchUnderscore.java
new file mode 100644
index 000000000000..a1bd84498768
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/normal/LowercaseDoesNotMatchUnderscore.java
@@ -0,0 +1,7 @@
+class X {
+  {
+    int _Web;
+    int web;
+    we<caret>x
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/codeInsight/completion/normalSorting/DispreferUnderscoredCaseMismatch.java b/java/java-tests/testData/codeInsight/completion/normalSorting/DispreferUnderscoredCaseMismatch.java
deleted file mode 100644
index db60d1c670e5..000000000000
--- a/java/java-tests/testData/codeInsight/completion/normalSorting/DispreferUnderscoredCaseMismatch.java
+++ /dev/null
@@ -1,5 +0,0 @@
-class Zoo {
-  void zoo(String fooBar, String __FOO_BAR) {
-    foo<caret>
-  }
-}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionOrderingTest.groovy b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionOrderingTest.groovy
index ca5c1f9e67fc..46257504acf2 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionOrderingTest.groovy
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionOrderingTest.groovy
@@ -443,10 +443,6 @@ interface TxANotAnno {}
     checkPreferredItems(0, 'fooBar', '_fooBar', 'FooBar')
   }
 
-  void testDispreferUnderscoredCaseMismatch() {
-    checkPreferredItems(0, 'fooBar', '__FOO_BAR')
-  }
-
   void testStatisticsMattersOnNextCompletion() {
     configureByFile(getTestName(false) + ".java")
     myFixture.completeBasic()
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionTest.groovy b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionTest.groovy
index acb27fe735c7..58b6ba2a6a2e 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionTest.groovy
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/NormalCompletionTest.groovy
@@ -1821,4 +1821,9 @@ class Bar {
     checkResult()
   }
 
+  void testLowercaseDoesNotMatchUnderscore() {
+    configure()
+    assert myFixture.lookupElementStrings == ['web']
+  }
+
 }
diff --git a/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CamelHumpMatcher.java b/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CamelHumpMatcher.java
index 790ad4a886a4..73923b6e395c 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CamelHumpMatcher.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CamelHumpMatcher.java
@@ -62,6 +62,12 @@ public class CamelHumpMatcher extends PrefixMatcher {
 
   @Override
   public boolean prefixMatches(@NotNull final String name) {
+    if (name.startsWith("_") &&
+        myPrefix.length() > 0 && Character.isLetter(myPrefix.charAt(0)) &&
+        CodeInsightSettings.getInstance().COMPLETION_CASE_SENSITIVE == CodeInsightSettings.FIRST_LETTER) {
+      return false;
+    }
+
     return myMatcher.matches(name);
   }
 
diff --git a/python/testSrc/com/jetbrains/python/PythonCompletionTest.java b/python/testSrc/com/jetbrains/python/PythonCompletionTest.java
index 39f3698a7e89..b99354a514ba 100644
--- a/python/testSrc/com/jetbrains/python/PythonCompletionTest.java
+++ b/python/testSrc/com/jetbrains/python/PythonCompletionTest.java
@@ -23,7 +23,6 @@ import com.intellij.codeInsight.lookup.Lookup;
 import com.intellij.codeInsight.lookup.LookupElement;
 import com.intellij.codeInsight.lookup.LookupElementBuilder;
 import com.intellij.testFramework.PsiTestUtil;
-import com.jetbrains.python.documentation.PyDocumentationSettings;
 import com.jetbrains.python.documentation.docstrings.DocStringFormat;
 import com.jetbrains.python.fixtures.PyTestCase;
 import com.jetbrains.python.psi.LanguageLevel;
@@ -1068,7 +1067,7 @@ public class PythonCompletionTest extends PyTestCase {
                                                 "@six.add_metaclass(M)\n" +
                                                 "class C(object):\n" +
                                                 "    def foo(self):\n" +
-                                                "        C.ba<caret>()");
+                                                "        C.ba<caret>x()");
 
     assertNotNull(suggested);
     assertContainsElements(suggested, "baz");
@@ -1082,7 +1081,7 @@ public class PythonCompletionTest extends PyTestCase {
                                                 "@a_m(M)\n" +
                                                 "class C(object):\n" +
                                                 "    def foo(self):\n" +
-                                                "        C.ba<caret>()");
+                                                "        C.ba<caret>x()");
 
     assertNotNull(suggested);
     assertContainsElements(suggested, "baz");