diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3a65989f3..3537aee94 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,10 +15,15 @@
 - Bump OR-Tools v7.8 [#107](https://github.com/Mapotempo/optimizer-api/pull/107)
 - VROOM were previously always called synchronously, it is now reserved to a set of effective `router_mode` (:car, :truck_medium) within a limit of points (<200). [#107](https://github.com/Mapotempo/optimizer-api/pull/107)
 
+### Removed
+
+
 ### Fixed
 
 - `unassigned` output were in some cases returning the key `shipment_id` instead of `pickup_shipment_id` and `delivery_shipment_id` [#107](https://github.com/Mapotempo/optimizer-api/pull/107)
 - Uniformize route content and always return `original_vehicle_id` [#107](https://github.com/Mapotempo/optimizer-api/pull/107)
+- Infeasibility detection of services with negative quantity [#111](https://github.com/Mapotempo/optimizer-api/pull/111)
+
 
 ## [v0.1.5] - 2021-01-05
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 664cc0de3..17c05bc34 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -202,6 +202,7 @@ def self.vehicle_and_days_partitions
 module VRP # rubocop: disable Metrics/ModuleLength, Style/CommentedKeyword
   def self.toy
     {
+      units: [{ id: 'u1' }],
       points: [{
         id: 'p1',
         location: {
diff --git a/test/wrapper_test.rb b/test/wrapper_test.rb
index fc9299ccd..a45ea6b3c 100644
--- a/test/wrapper_test.rb
+++ b/test/wrapper_test.rb
@@ -2820,6 +2820,17 @@ def test_impossible_service_too_long
     assert_empty OptimizerWrapper.config[:services][:demo].detect_unfeasible_services(TestHelper.create(vrp))
   end
 
+  def test_impossible_service_with_negative_quantity
+    vrp = VRP.toy
+    vrp[:services].first[:quantities] = [{ unit_id: 'u1', value: -5 }]
+    vrp[:vehicles].first[:capacities] = [{ unit_id: 'u1', limit: 5 }]
+    assert_empty OptimizerWrapper.config[:services][:demo].detect_unfeasible_services(TestHelper.create(vrp))
+
+    vrp[:services].first[:quantities].first[:value] = -6
+    result = OptimizerWrapper.config[:services][:demo].detect_unfeasible_services(TestHelper.create(vrp))
+    assert_equal(1, result.count{ |un| un[:reason] == 'Service quantity greater than any vehicle capacity' })
+  end
+
   def test_feasible_if_tardiness_allowed
     vrp = VRP.basic
 
diff --git a/wrappers/wrapper.rb b/wrappers/wrapper.rb
index bc1acc53e..d81aa4d27 100644
--- a/wrappers/wrapper.rb
+++ b/wrappers/wrapper.rb
@@ -750,7 +750,7 @@ def detect_unfeasible_services(vrp)
 
       vrp.services.each{ |service|
         service.quantities.each{ |qty|
-          if vehicle_max_capacities[qty.unit_id] && qty.value && vehicle_max_capacities[qty.unit_id] < qty.value
+          if vehicle_max_capacities[qty.unit_id] && qty.value && vehicle_max_capacities[qty.unit_id] < qty.value.abs
             add_unassigned(unfeasible, vrp, service, 'Service quantity greater than any vehicle capacity')
             break
           end