diff --git a/postgres/variables.tf b/postgres/variables.tf
index 886fd59..f1906fa 100644
--- a/postgres/variables.tf
+++ b/postgres/variables.tf
@@ -55,10 +55,26 @@ variable "postgres_instance_region" {
 
 # Postgres User and DB Configs
 variable "postgres_databases" {
-  description   = "list of users and databases"
-  type          = list(object({
-    db_name     = string       # db name inside the instance
-    user_name   = string       # username and owner for postgres db
-    user_roles  = list(string) # List of database access levels for the user. Supported values are: login, createdb.
+  description = "list of users and databases"
+  type = list(object({
+    db_name    = string       # db name inside the instance
+    user_name  = string       # username and owner for postgres db
+    user_roles = list(string) # List of database access levels for the user. Supported values are: login, createdb.
   }))
-}
\ No newline at end of file
+
+  # -----------------------------------------------------------------
+  # Validation: each db_name must be unique
+  # -----------------------------------------------------------------
+  validation {
+    condition     = length(distinct([for db in var.postgres_databases : db.db_name])) == length(var.postgres_databases)
+    error_message = "Each db_name must be unique."
+  }
+
+  # -----------------------------------------------------------------
+  # Validation: each user_name must be unique
+  # -----------------------------------------------------------------
+  validation {
+    condition     = length(distinct([for db in var.postgres_databases : db.user_name])) == length(var.postgres_databases)
+    error_message = "Each user_name must be unique."
+  }
+}