diff --git a/pdfminer/pdfparser.py b/pdfminer/pdfparser.py
index e2ac6cf..f1b6c7f 100644
--- a/pdfminer/pdfparser.py
+++ b/pdfminer/pdfparser.py
@@ -151,6 +151,7 @@ class PDFStreamParser(PDFParser):
         self.add_results(*self.popall())
         return
 
+    KEYWORD_OBJ = KWD('obj')
     def do_keyword(self, pos, token):
         if token is self.KEYWORD_R:
             # reference to indirect object
@@ -162,6 +163,12 @@ class PDFStreamParser(PDFParser):
             except PSSyntaxError:
                 pass
             return
+        elif token in (self.KEYWORD_OBJ, self.KEYWORD_ENDOBJ):
+            if STRICT:
+                # See PDF Spec 3.4.6: Only the object values are stored in the
+                # stream; the obj and endobj keywords are not used.
+                raise PDFSyntaxError("Keyword endobj found in stream")
+            return
         # others
         self.push((pos, token))
         return