diff --git a/tests/README b/tests/README
index 1e4633b675..776545e88a 100644
--- a/tests/README
+++ b/tests/README
@@ -1,3 +1,6 @@
 This directory contains a series of test scripts which are used to
 verify basic functionality of the LDAP libraries, slapd, and slurpd.
 To run the tests, type "make" in the ./tests directory.
+
+To modify the debug level the tests run slapd with, set the SLAPD_DEBUG
+environment variable.
diff --git a/tests/scripts/defines.sh b/tests/scripts/defines.sh
index 8d84c1f726..b851971146 100755
--- a/tests/scripts/defines.sh
+++ b/tests/scripts/defines.sh
@@ -34,7 +34,7 @@ LDAPMODIFY=../clients/tools/ldapmodify
 LDAPADD=../clients/tools/ldapadd
 LDAPMODRDN=../clients/tools/ldapmodrdn
 SLAPDTESTER=$PROGDIR/slapd-tester
-LVL=5
+LVL=${SLAPD_DEBUG-5}
 ADDR=127.0.0.1
 PORT=9009
 SLAVEPORT=9010