diff --git a/.gitignore b/.gitignore
index 7c0e238bd..4145a7a82 100644
--- a/.gitignore
+++ b/.gitignore
@@ -470,4 +470,3 @@ Makefile.in
 /tools/test.img
 /tools/virt-*.1
 /tools/virt-*.pl
-/valgrind.log*
diff --git a/configure.ac b/configure.ac
index 6bace0756..2fdf66ec0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -919,7 +919,7 @@ AS_IF([test "x$VALGRIND" != "xno"],[
     fi
 
     # Substitute the whole valgrind command.
-    VG='$(VALGRIND) $(VALGRIND_NO_VGDB) --log-file=$(abs_top_builddir)/valgrind.log --leak-check=full --error-exitcode=119 --suppressions=$(abs_top_srcdir)/valgrind-suppressions'
+    VG='$(VALGRIND) $(VALGRIND_NO_VGDB) --log-file=$(abs_top_builddir)/tmp/valgrind-%q{T}-%p.log --leak-check=full --error-exitcode=119 --suppressions=$(abs_top_srcdir)/valgrind-suppressions'
     ],[
     # No valgrind, so substitute VG with something that will break.
     VG=VALGRIND_IS_NOT_INSTALLED
diff --git a/run.in b/run.in
index b978a17db..d7d4800e3 100755
--- a/run.in
+++ b/run.in
@@ -44,6 +44,10 @@ fi
 # Find this script.
 b=@abs_builddir@
 
+# Set T to current date & time (mainly for valgrind logfile name).
+T=`date +%Y%m%d.%H.%M.%S`
+export T
+
 # Set tmpdir and cachedir so the appliance doesn't conflict with
 # globally installed libguestfs.
 #
diff --git a/tmp/.gitignore b/tmp/.gitignore
index 27dc5056a..28ac388f3 100644
--- a/tmp/.gitignore
+++ b/tmp/.gitignore
@@ -2,3 +2,4 @@
 /guestfs.*
 /libguestfs??????/
 /run-*
+/valgrind-*.log