diff --git a/pkgs/servers/mail/exim/default.nix b/pkgs/servers/mail/exim/default.nix
index 6c1e05bbdbdb..122d00c5f0a7 100644
--- a/pkgs/servers/mail/exim/default.nix
+++ b/pkgs/servers/mail/exim/default.nix
@@ -60,7 +60,7 @@ stdenv.mkDerivation rec {
         s:^# \(LOOKUP_MYSQL_PC=libmysqlclient\)$:\1:
         s:^\(LOOKUP_LIBS\)=\(.*\):\1=\2 -lmysqlclient -L${libmysqlclient}/lib/mysql -lssl -ldl -lm -lpthread -lz:
         s:^# \(LOOKUP_LIBS\)=.*:\1=-lmysqlclient -L${libmysqlclient}/lib/mysql -lssl -ldl -lm -lpthread -lz:
-        s:^# \(LOOKUP_INCLUDE\)=.*:\1=-I${libmysqlclient}/include/mysql/:
+        s:^# \(LOOKUP_INCLUDE\)=.*:\1=-I${libmysqlclient.dev}/include/mysql/:
       ''}
       ${lib.optionalString enableAuthDovecot ''
         s:^# \(AUTH_DOVECOT\)=.*:\1=yes: