diff --git a/registrasion/controllers/cart.py b/registrasion/controllers/cart.py
index 95a2b92173ea5afc7a149fac60031a922fcd6656..a643863f757dd5e2728d7380f847996d12e0b078 100644
--- a/registrasion/controllers/cart.py
+++ b/registrasion/controllers/cart.py
@@ -10,6 +10,7 @@ from django.db.models import Max
 from django.utils import timezone
 
 from registrasion import models as rego
+from registrasion.exceptions import CartValidationError
 
 from category import CategoryController
 from conditions import ConditionController
@@ -114,22 +115,25 @@ class CartController(object):
         ''' Tests that the quantity changes we intend to make do not violate
         the limits and enabling conditions imposed on the products. '''
 
+        errors = []
+
         # Test each product limit here
         for product, quantity in product_quantities:
             if quantity < 0:
                 # TODO: batch errors
-                raise ValidationError("Value must be zero or greater.")
+                errors.append((product, "Value must be zero or greater."))
 
             prod = ProductController(product)
             limit = prod.user_quantity_remaining(self.cart.user)
 
             if quantity > limit:
                 # TODO: batch errors
-                raise ValidationError(
+                errors.append((
+                    product,
                     "You may only have %d of product: %s" % (
-                        limit, product.name,
+                        limit, product,
                     )
-                )
+                ))
 
         # Collect by category
         by_cat = collections.defaultdict(list)
@@ -137,20 +141,21 @@ class CartController(object):
             by_cat[product.category].append((product, quantity))
 
         # Test each category limit here
-        for cat in by_cat:
-            ctrl = CategoryController(cat)
+        for category in by_cat:
+            ctrl = CategoryController(category)
             limit = ctrl.user_quantity_remaining(self.cart.user)
 
             # Get the amount so far in the cart
-            to_add = sum(i[1] for i in by_cat[cat])
+            to_add = sum(i[1] for i in by_cat[category])
 
             if to_add > limit:
                 # TODO: batch errors
-                raise ValidationError(
+                errors.append((
+                    category,
                     "You may only have %d items in category: %s" % (
-                        limit, cat.name,
+                        limit, category.name,
                     )
-                )
+                ))
 
         # Test the enabling conditions
         errs = ConditionController.test_enabling_conditions(
@@ -160,7 +165,12 @@ class CartController(object):
 
         if errs:
             # TODO: batch errors
-            raise ValidationError("An enabling condition failed")
+            errors.append(
+                ("enabling_conditions", "An enabling condition failed")
+            )
+
+        if errors:
+            raise CartValidationError(errors)
 
     def apply_voucher(self, voucher_code):
         ''' Applies the voucher with the given code to this cart. '''
diff --git a/registrasion/controllers/category.py b/registrasion/controllers/category.py
index 9ab9dd3be9bb44b2f3ca36eed272cda12db4cc46..04f502db1ff67d9e1eeec98c4aa04048a3fb7575 100644
--- a/registrasion/controllers/category.py
+++ b/registrasion/controllers/category.py
@@ -53,4 +53,4 @@ class CategoryController(object):
         )
 
         cat_count = items.aggregate(Sum("quantity"))["quantity__sum"] or 0
-        cat_limit - cat_count
+        return cat_limit - cat_count
diff --git a/registrasion/exceptions.py b/registrasion/exceptions.py
new file mode 100644
index 0000000000000000000000000000000000000000..ac6624d9aab7b65e17db73eceda69e44c87550f6
--- /dev/null
+++ b/registrasion/exceptions.py
@@ -0,0 +1,4 @@
+from django.core.exceptions import ValidationError
+
+class CartValidationError(ValidationError):
+    pass
diff --git a/registrasion/views.py b/registrasion/views.py
index 192f401d2fa0c63c1abc207ca2c972dfb7038697..77c00bb3f4b1231f6cdeb6d37e8c075f52adf962 100644
--- a/registrasion/views.py
+++ b/registrasion/views.py
@@ -6,6 +6,7 @@ from registrasion.controllers import discount
 from registrasion.controllers.cart import CartController
 from registrasion.controllers.invoice import InvoiceController
 from registrasion.controllers.product import ProductController
+from registrasion.exceptions import CartValidationError
 
 from collections import namedtuple
 
@@ -321,15 +322,24 @@ def handle_products(request, category, products, prefix):
 
 def set_quantities_from_products_form(products_form, current_cart):
 
-    quantities = products_form.product_quantities()
+    quantities = list(products_form.product_quantities())
     product_quantities = [
         (rego.Product.objects.get(pk=i[0]), i[1]) for i in quantities
     ]
+    field_names = dict(
+        (i[0][0], i[1][2]) for i in zip(product_quantities, quantities)
+    )
 
     try:
         current_cart.set_quantities(product_quantities)
-    except ValidationError as ve:
-        products_form.add_error(None, ve)
+    except CartValidationError as ve:
+        for ve_field in ve.error_list:
+            product, message = ve_field.message
+            if product in field_names:
+                field = field_names[product]
+            else:
+                field = None
+            products_form.add_error(field, message)
 
 
 def handle_voucher(request, prefix):