diff --git a/dawn.json b/dawn.json
index 7528d46..d1c321f 100644
--- a/dawn.json
+++ b/dawn.json
@@ -776,7 +776,7 @@
                     {"name": "index count", "type": "uint32_t"},
                     {"name": "instance count", "type": "uint32_t"},
                     {"name": "first index", "type": "uint32_t"},
-                    {"name": "base vertex", "type": "uint32_t"},
+                    {"name": "base vertex", "type": "int32_t"},
                     {"name": "first instance", "type": "uint32_t"}
                 ]
             },
diff --git a/src/dawn_native/Commands.h b/src/dawn_native/Commands.h
index 091547c..26e0b68 100644
--- a/src/dawn_native/Commands.h
+++ b/src/dawn_native/Commands.h
@@ -143,7 +143,7 @@
         uint32_t indexCount;
         uint32_t instanceCount;
         uint32_t firstIndex;
-        uint32_t baseVertex;
+        int32_t baseVertex;
         uint32_t firstInstance;
     };
 
diff --git a/src/dawn_native/RenderPassEncoder.cpp b/src/dawn_native/RenderPassEncoder.cpp
index 9288c6a..7470063 100644
--- a/src/dawn_native/RenderPassEncoder.cpp
+++ b/src/dawn_native/RenderPassEncoder.cpp
@@ -60,7 +60,7 @@
     void RenderPassEncoderBase::DrawIndexed(uint32_t indexCount,
                                             uint32_t instanceCount,
                                             uint32_t firstIndex,
-                                            uint32_t baseVertex,
+                                            int32_t baseVertex,
                                             uint32_t firstInstance) {
         if (mTopLevelEncoder->ConsumedError(ValidateCanRecordCommands())) {
             return;
diff --git a/src/dawn_native/RenderPassEncoder.h b/src/dawn_native/RenderPassEncoder.h
index ccc776f..7e8243e 100644
--- a/src/dawn_native/RenderPassEncoder.h
+++ b/src/dawn_native/RenderPassEncoder.h
@@ -40,7 +40,7 @@
         void DrawIndexed(uint32_t vertexCount,
                          uint32_t instanceCount,
                          uint32_t firstIndex,
-                         uint32_t baseVertex,
+                         int32_t baseVertex,
                          uint32_t firstInstance);
 
         void SetPipeline(RenderPipelineBase* pipeline);
diff --git a/src/tests/end2end/DrawIndexedTests.cpp b/src/tests/end2end/DrawIndexedTests.cpp
index c1b889e..02421c7 100644
--- a/src/tests/end2end/DrawIndexedTests.cpp
+++ b/src/tests/end2end/DrawIndexedTests.cpp
@@ -67,9 +67,11 @@
                  1.0f, -1.0f, 0.0f, 1.0f,
                 -1.0f,  1.0f, 0.0f, 1.0f
             });
-            indexBuffer = utils::CreateBufferFromData<uint32_t>(device, dawn::BufferUsageBit::Index, {
-                0, 1, 2, 0, 3, 1
-            });
+            indexBuffer = utils::CreateBufferFromData<uint32_t>(
+                device, dawn::BufferUsageBit::Index,
+                {0, 1, 2, 0, 3, 1,
+                 // The indices below are added to test negatve baseVertex
+                 0 + 4, 1 + 4, 2 + 4, 0 + 4, 3 + 4, 1 + 4});
         }
 
         utils::BasicRenderPass renderPass;
@@ -77,8 +79,13 @@
         dawn::Buffer vertexBuffer;
         dawn::Buffer indexBuffer;
 
-        void Test(uint32_t indexCount, uint32_t instanceCount, uint32_t firstIndex,
-                  uint32_t baseVertex, uint32_t firstInstance, RGBA8 bottomLeftExpected,
+        void Test(uint32_t indexCount,
+                  uint32_t instanceCount,
+                  uint32_t firstIndex,
+                  int32_t baseVertex,
+                  uint32_t firstInstance,
+                  uint64_t bufferOffset,
+                  RGBA8 bottomLeftExpected,
                   RGBA8 topRightExpected) {
             uint64_t zeroOffset = 0;
             dawn::CommandEncoder encoder = device.CreateCommandEncoder();
@@ -87,7 +94,7 @@
                     &renderPass.renderPassInfo);
                 pass.SetPipeline(pipeline);
                 pass.SetVertexBuffers(0, 1, &vertexBuffer, &zeroOffset);
-                pass.SetIndexBuffer(indexBuffer, 0);
+                pass.SetIndexBuffer(indexBuffer, bufferOffset);
                 pass.DrawIndexed(indexCount, instanceCount, firstIndex, baseVertex, firstInstance);
                 pass.EndPass();
             }
@@ -107,13 +114,13 @@
     RGBA8 notFilled(0, 0, 0, 0);
 
     // Test a draw with no indices.
-    Test(0, 0, 0, 0, 0, notFilled, notFilled);
+    Test(0, 0, 0, 0, 0, 0, notFilled, notFilled);
     // Test a draw with only the first 3 indices of the first quad (bottom left triangle)
-    Test(3, 1, 0, 0, 0, filled, notFilled);
+    Test(3, 1, 0, 0, 0, 0, filled, notFilled);
     // Test a draw with only the last 3 indices of the first quad (top right triangle)
-    Test(3, 1, 3, 0, 0, notFilled, filled);
+    Test(3, 1, 3, 0, 0, 0, notFilled, filled);
     // Test a draw with all 6 indices (both triangles).
-    Test(6, 1, 0, 0, 0, filled, filled);
+    Test(6, 1, 0, 0, 0, 0, filled, filled);
 }
 
 // Test the parameter 'baseVertex' of DrawIndexed() works.
@@ -122,9 +129,15 @@
     RGBA8 notFilled(0, 0, 0, 0);
 
     // Test a draw with only the first 3 indices of the second quad (top right triangle)
-    Test(3, 1, 0, 4, 0, notFilled, filled);
+    Test(3, 1, 0, 4, 0, 0, notFilled, filled);
     // Test a draw with only the last 3 indices of the second quad (bottom left triangle)
-    Test(3, 1, 3, 4, 0, filled, notFilled);
+    Test(3, 1, 3, 4, 0, 0, filled, notFilled);
+
+    // Test negative baseVertex
+    // Test a draw with only the first 3 indices of the first quad (bottom left triangle)
+    Test(3, 1, 0, -4, 0, 6 * sizeof(uint32_t), filled, notFilled);
+    // Test a draw with only the last 3 indices of the first quad (top right triangle)
+    Test(3, 1, 3, -4, 0, 6 * sizeof(uint32_t), notFilled, filled);
 }
 
 DAWN_INSTANTIATE_TEST(DrawIndexedTest, D3D12Backend, MetalBackend, OpenGLBackend, VulkanBackend);