diff --git a/valgrind.suppressions b/valgrind.suppressions
index 23f68d970d3..37674622344 100644
--- a/valgrind.suppressions
+++ b/valgrind.suppressions
@@ -5,4 +5,18 @@
    fun:_ZNSsC1EPKcRKSaIcE
    ...
 }
+{
+   mongod-writes-uninitialized-data-for-preallocate
+   Memcheck:Param
+   write(buf)
+   obj:/lib64/libpthread-2.14.90.so
+   fun:_ZN5mongo7LogFile17synchronousAppendEPKvm
+   fun:_ZN5mongo3dur20_preallocateIsFasterEv
+   fun:_ZN5mongo3dur19preallocateIsFasterEv
+   fun:_ZN5mongo3dur16preallocateFilesEv
+   fun:_ZN5mongo3dur7startupEv
+   fun:_ZN5mongo14_initAndListenEi
+   fun:_ZN5mongo13initAndListenEi
+   fun:main
+}