diff --git a/pgbouncer_exporter.go b/pgbouncer_exporter.go
index f4cbaa0..307d1d9 100644
--- a/pgbouncer_exporter.go
+++ b/pgbouncer_exporter.go
@@ -46,7 +46,7 @@ func main() {
 	flag.AddFlags(kingpin.CommandLine, promlogConfig)
 
 	var (
-		connectionStringPointer = kingpin.Flag("pgBouncer.connectionString", "Connection string for accessing pgBouncer.").Default("postgres://postgres:@localhost:6543/pgbouncer?sslmode=disable").String()
+		connectionStringPointer = kingpin.Flag("pgBouncer.connectionString", "Connection string for accessing pgBouncer.").Default("postgres://postgres:@localhost:6543/pgbouncer?sslmode=disable").Envar("PGBOUNCER_EXPORTER_CONNECTION_STRING").String()
 		metricsPath             = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").String()
 		pidFilePath             = kingpin.Flag("pgBouncer.pid-file", pidFileHelpText).Default("").String()
 	)