diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9054ad4987..1c4d5d50df 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,11 @@
 - Integration between Interpolation and Modules has been changed to not generate invalid HCL references
   ([Issue #219](https://github.com/cycloidio/terracognita/issues/219)
 
+### Fixed
+
+- Variables names will now be normalized to be valid HCL
+  ([PUll #219](https://github.com/cycloidio/terracognita/pull/227)
+
 ## [0.7.2] _2021-08-13_
 
 ### Added
diff --git a/hcl/writer.go b/hcl/writer.go
index c84c7ceea3..b199fed7e0 100644
--- a/hcl/writer.go
+++ b/hcl/writer.go
@@ -15,6 +15,7 @@ import (
 	"github.com/cycloidio/terracognita/errcode"
 	"github.com/cycloidio/terracognita/log"
 	"github.com/cycloidio/terracognita/provider"
+	"github.com/cycloidio/terracognita/util"
 	"github.com/cycloidio/terracognita/writer"
 	"github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/pkg/errors"
@@ -362,7 +363,7 @@ func walkVariables(cfg map[string]interface{}, validVariables map[string]struct{
 		case []interface{}:
 			if len(v) == 0 {
 				if hasKey(validVariables, currentKey) {
-					varName := strings.ReplaceAll(currentKey, ".", "_")
+					varName := util.NormalizeName(strings.ReplaceAll(currentKey, ".", "_"))
 					variables[varName] = map[string]interface{}{
 						"default": cfg[key],
 					}
@@ -378,7 +379,7 @@ func walkVariables(cfg map[string]interface{}, validVariables map[string]struct{
 				}
 			} else {
 				if hasKey(validVariables, currentKey) {
-					varName := strings.ReplaceAll(currentKey, ".", "_")
+					varName := util.NormalizeName(strings.ReplaceAll(currentKey, ".", "_"))
 					variables[varName] = map[string]interface{}{
 						"default": cfg[key],
 					}
@@ -389,7 +390,7 @@ func walkVariables(cfg map[string]interface{}, validVariables map[string]struct{
 			// This means is a "simple" value so we can
 			// directly replace it with the variable
 			if hasKey(validVariables, currentKey) {
-				varName := strings.ReplaceAll(currentKey, ".", "_")
+				varName := util.NormalizeName(strings.ReplaceAll(currentKey, ".", "_"))
 				variables[varName] = map[string]interface{}{
 					"default": cfg[key],
 				}
diff --git a/hcl/writer_test.go b/hcl/writer_test.go
index 1c2f8d5908..81132058c1 100644
--- a/hcl/writer_test.go
+++ b/hcl/writer_test.go
@@ -332,6 +332,9 @@ resource "type" "name" {
 				"key":  "value",
 				"key2": "value",
 				"key3": []interface{}{},
+				"key4": map[string]interface{}{
+					"nested:key:4": "value4",
+				},
 			}
 			ehcl = `
 resource "type" "name" {
@@ -342,12 +345,16 @@ resource "type" "name2" {
   key = var.type_name2_key
 	key2 = var.type_name2_key2
 	key3 = var.type_name2_key3
+	key4 {
+		"nested:key:4" = var.type_name2_key4_nested_key_4
+	}
 }
 
 module "test" {
 	# type_name2_key = "value"
 	# type_name2_key2 = "value"
 	# type_name2_key3 = []
+	# type_name2_key4_nested_key_4 = "value4"
 	# type_name_key = "value"
   source = "./module-test"
 }
@@ -381,6 +388,10 @@ variable "type_name2_key3" {
 	default = []
 }
 
+variable "type_name2_key4_nested_key_4" {
+	default = "value4"
+}
+
 variable "type_name_key" {
 	default = "value"
 }
diff --git a/tag/tag.go b/tag/tag.go
index 072014edca..c9d3320950 100644
--- a/tag/tag.go
+++ b/tag/tag.go
@@ -11,6 +11,7 @@ import (
 	"github.com/aws/aws-sdk-go/service/rds"
 	"github.com/chr4/pwgen"
 	"github.com/cycloidio/terracognita/errcode"
+	"github.com/cycloidio/terracognita/util"
 	"github.com/hashicorp/hcl/v2/hclsyntax"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 )
@@ -18,7 +19,6 @@ import (
 // nameRegexp is the new regexp used to validate the names
 // of the resources on TF (defined on configs/configschema/internal_validate.go)
 var nameRegexp = regexp.MustCompile(`^[a-z0-9_]+$`)
-var invalidNameRegexp = regexp.MustCompile(`[^a-z0-9_]`)
 
 // Tag it's an easy representation of
 // a ec2.Filter for tags
@@ -75,8 +75,8 @@ func GetNameFromTag(key string, srd *schema.ResourceData, fallback string) strin
 		n = strings.ToLower(name.(string))
 	}
 
-	forcedN := forceResourceName(n)
-	forcedFallback := forceResourceName(fallback)
+	forcedN := util.NormalizeName(n)
+	forcedFallback := util.NormalizeName(fallback)
 
 	if isValidResourceName(n) && hclsyntax.ValidIdentifier(n) {
 		return n
@@ -97,12 +97,6 @@ func isValidResourceName(name string) bool {
 	return nameRegexp.MatchString(name)
 }
 
-// forceResourceName will try to replace all the
-// invalid characters of the name for _
-func forceResourceName(name string) string {
-	return invalidNameRegexp.ReplaceAllString(name, "_")
-}
-
 // GetOtherTags used to check other possible tag attributes on resources
 func GetOtherTags(provider string, srd *schema.ResourceData, filterTag Tag) (string, bool) {
 	// keep the same logic as r.data.GetOk
diff --git a/util/name.go b/util/name.go
new file mode 100644
index 0000000000..8697decff0
--- /dev/null
+++ b/util/name.go
@@ -0,0 +1,14 @@
+package util
+
+import (
+	"regexp"
+	"strings"
+)
+
+var invalidNameRegexp = regexp.MustCompile(`[^a-z0-9_]`)
+
+// NormalizeName will convert the n into an low case alphanumeric value
+// and the invalid characters will be replaced by '_'
+func NormalizeName(n string) string {
+	return invalidNameRegexp.ReplaceAllString(strings.ToLower(n), "_")
+}
diff --git a/util/name_test.go b/util/name_test.go
new file mode 100644
index 0000000000..1b786d37a8
--- /dev/null
+++ b/util/name_test.go
@@ -0,0 +1,37 @@
+package util_test
+
+import (
+	"testing"
+
+	"github.com/cycloidio/terracognita/util"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNormalizeName(t *testing.T) {
+	tests := []struct {
+		Name     string
+		In       string
+		Expected string
+	}{
+		{
+			Name:     "NoChange",
+			In:       "in",
+			Expected: "in",
+		},
+		{
+			Name:     "UpperCase",
+			In:       "IN",
+			Expected: "in",
+		},
+		{
+			Name:     "Invalid",
+			In:       ":a",
+			Expected: "_a",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			assert.Equal(t, tt.Expected, util.NormalizeName(tt.In))
+		})
+	}
+}