diff --git a/recipes/forms.py b/recipes/forms.py
index 1a49779..3b4c6d9 100644
--- a/recipes/forms.py
+++ b/recipes/forms.py
@@ -1,4 +1,4 @@
-from django.forms import ModelForm, BooleanField
+from django.forms import ModelForm, BooleanField, ValidationError
 from .models import Recipe, Version, Ingredient
 
 class VersionForm(ModelForm):
@@ -6,4 +6,10 @@ class VersionForm(ModelForm):
 		model = Version
 		fields = ['label', 'slug', 'body']
 
-	# use_author_user = BooleanField(initial=True)
+	def clean_slug(self):
+		slug = self.cleaned_data['slug']
+		if Version.objects.filter(slug=slug).exists():
+			raise ValidationError('A recipe version with this slug already exists.')
+		return slug
+
+# use_author_user = BooleanField(initial=True)