diff --git a/Makefile b/Makefile
index 8919dabc78..76511045a8 100644
--- a/Makefile
+++ b/Makefile
@@ -82,10 +82,6 @@ all:
 # Define NO_ACCURATE_DIFF if your diff program at least sometimes misses
 # a missing newline at the end of the file.
 #
-# Define COLLISION_CHECK below if you believe that SHA1's
-# 1461501637330902918203684832716283019655932542976 hashes do not give you
-# sufficient guarantee that no collisions between objects will ever happen.
-#
 # Define USE_NSEC below if you want git to care about sub-second file mtimes
 # and ctimes. Note that you need recent glibc (at least 2.2.4) for this, and
 # it will BREAK YOUR LOCAL DIFFS! show-diff and anything using it will likely
diff --git a/configure.ac b/configure.ac
index 34e34789bd..e153d53823 100644
--- a/configure.ac
+++ b/configure.ac
@@ -316,10 +316,6 @@ GIT_PARSE_WITH(iconv))
 
 ## --enable-FEATURE[=ARG] and --disable-FEATURE
 #
-# Define COLLISION_CHECK below if you believe that SHA1's
-# 1461501637330902918203684832716283019655932542976 hashes do not give you
-# sufficient guarantee that no collisions between objects will ever happen.
-#
 # Define USE_NSEC below if you want git to care about sub-second file mtimes
 # and ctimes. Note that you need recent glibc (at least 2.2.4) for this, and
 # it will BREAK YOUR LOCAL DIFFS! show-diff and anything using it will likely