diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 68186c60e..459a0f43e 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -4850,6 +4850,20 @@ bool Tokenizer::simplifyConditions()
             ret = true;
         }
 
+        else if (Token::simpleMatch(tok, "( true ||") ||
+                 Token::simpleMatch(tok, "( false &&"))
+        {
+            Token::eraseTokens(tok->next(), tok->link());
+            ret = true;
+        }
+
+        else if (Token::simpleMatch(tok, "|| true )") ||
+                 Token::simpleMatch(tok, "&& false )"))
+        {
+            Token::eraseTokens(tok->tokAt(2)->link(), tok->next());
+            ret = true;
+        }
+
         // Change numeric constant in condition to "true" or "false"
         if (Token::Match(tok, "if|while ( %num%") &&
             (tok->tokAt(3)->str() == ")" || tok->tokAt(3)->str() == "||" || tok->tokAt(3)->str() == "&&"))
@@ -6344,6 +6358,16 @@ bool Tokenizer::simplifyKnownVariables()
                         ret = true;
                     }
 
+                    // condition "(|&&|%OROR% %varid% )|&&|%OROR%
+                    if (!Token::Match(tok3->previous(), "( %var% )") &&
+                        (Token::Match(tok3->previous(), "&&|(") || tok3->strAt(-1) == "||") &&
+                        tok3->varId() == varid &&
+                        (Token::Match(tok3->next(), "&&|)") || tok3->strAt(1) == "||"))
+                    {
+                        tok3->str(value);
+                        ret = true;
+                    }
+
                     // Variable is used somehow in a non-defined pattern => bail out
                     if (tok3->varId() == varid)
                     {
diff --git a/test/testsimplifytokens.cpp b/test/testsimplifytokens.cpp
index f351cbaec..f57bde0f4 100644
--- a/test/testsimplifytokens.cpp
+++ b/test/testsimplifytokens.cpp
@@ -241,6 +241,7 @@ private:
 
         TEST_CASE(reverseArraySyntax)
         TEST_CASE(simplify_numeric_condition)
+        TEST_CASE(simplify_condition);
 
         TEST_CASE(pointeralias1);
         TEST_CASE(pointeralias2);
@@ -5454,6 +5455,45 @@ private:
         }
     }
 
+    void simplify_condition()
+    {
+        {
+            const char code[] =
+                "void f(int a)\n"
+                "{\n"
+                "if (a && false) g();\n"
+                "}";
+            ASSERT_EQUALS("void f ( int a ) { }", tok(code));
+        }
+
+        {
+            const char code[] =
+                "void f(int a)\n"
+                "{\n"
+                "if (false && a) g();\n"
+                "}";
+            ASSERT_EQUALS("void f ( int a ) { }", tok(code));
+        }
+
+        {
+            const char code[] =
+                "void f(int a)\n"
+                "{\n"
+                "if (true || a) g();\n"
+                "}";
+            ASSERT_EQUALS("void f ( int a ) { { g ( ) ; } }", tok(code));
+        }
+
+        {
+            const char code[] =
+                "void f(int a)\n"
+                "{\n"
+                "if (a || true) g();\n"
+                "}";
+            ASSERT_EQUALS("void f ( int a ) { { g ( ) ; } }", tok(code));
+        }
+    }
+
 
     void pointeralias1()
     {
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index b81c698fc..82460bbf6 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -126,6 +126,7 @@ private:
         TEST_CASE(simplifyKnownVariables35);    // ticket #2353 - False positive: Division by zero 'if (x == 0) return 0; return 10 / x;'
         TEST_CASE(simplifyKnownVariables36);    // ticket #2304 - known value for strcpy parameter
         TEST_CASE(simplifyKnownVariables37);    // ticket #2398 - false positive caused by no simplification in for loop
+        TEST_CASE(simplifyKnownVariables38);    // ticket #2399 - simplify conditions
         TEST_CASE(simplifyKnownVariablesBailOutAssign);
         TEST_CASE(simplifyKnownVariablesBailOutFor1);
         TEST_CASE(simplifyKnownVariablesBailOutFor2);
@@ -1941,6 +1942,22 @@ private:
         ASSERT_EQUALS(expected, tokenizeAndStringify(code, true));
     }
 
+    void simplifyKnownVariables38()
+    {
+        // Ticket #2399 - simplify conditions
+        const char code[] = "void f() {\n"
+                            "    int x = 0;\n"
+                            "    int y = 1;\n"
+                            "    if (x || y);\n"
+                            "}";
+        const char expected[] = "void f ( ) {\n"
+                                ";\n"
+                                "\n"
+                                "{ ; }\n"
+                                "}";
+        ASSERT_EQUALS(expected, tokenizeAndStringify(code, true));
+    }
+
     void simplifyKnownVariablesBailOutAssign()
     {
         const char code[] = "int foo() {\n"