diff --git a/lib/controller/checks.py b/lib/controller/checks.py
index bd751a484..01d2a30c5 100644
--- a/lib/controller/checks.py
+++ b/lib/controller/checks.py
@@ -322,6 +322,9 @@ def checkSqlInjection(place, parameter, value):
                                 boundPayload = agent.suffixQuery(boundPayload, comment, suffix, where)
                                 cmpPayload = agent.payload(place, parameter, newValue=boundPayload, where=where)
 
+                                pushValue(kb.negativeLogic)
+                                kb.negativeLogic = "OR NOT" in cmpPayload
+
                                 return cmpPayload
 
                             # Useful to set kb.matchRatio at first based on
@@ -347,6 +350,8 @@ def checkSqlInjection(place, parameter, value):
 
                                     injectable = True
 
+                            kb.negativeLogic = popValue()
+
                         # In case of error-based SQL injection
                         elif method == PAYLOAD.METHOD.GREP:
                             # Perform the test's request and grep the response
diff --git a/lib/request/comparison.py b/lib/request/comparison.py
index e0329bea0..d15e336f1 100644
--- a/lib/request/comparison.py
+++ b/lib/request/comparison.py
@@ -36,7 +36,7 @@ def comparison(page, headers, code=None, getRatioValue=False, pageLength=None):
     seqMatcher.set_seq1(kb.pageTemplate)
 
     def _(condition):
-        #condition = not condition if kb.negativeLogic else condition
+        condition = not condition if kb.negativeLogic else condition
         return condition if not getRatioValue else (MAX_RATIO if condition else MIN_RATIO)
 
     if any([conf.string, conf.regexp]):