diff --git a/src/cfgparse.c b/src/cfgparse.c
index 2400559..3fee54e 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -9098,6 +9098,13 @@
 {
 	struct cfg_section *cs;
 
+	list_for_each_entry(cs, &sections, list) {
+		if (strcmp(cs->section_name, section_name) == 0) {
+			Alert("register section '%s': already registered.\n", section_name);
+			return 0;
+		}
+	}
+
 	cs = calloc(1, sizeof(*cs));
 	if (!cs) {
 		Alert("register section '%s': out of memory.\n", section_name);