diff --git a/dlls/d3d10core/tests/d3d10core.c b/dlls/d3d10core/tests/d3d10core.c
index 6ec398269fa..b8338152bb7 100644
--- a/dlls/d3d10core/tests/d3d10core.c
+++ b/dlls/d3d10core/tests/d3d10core.c
@@ -5533,6 +5533,20 @@ float4 main(float4 color : COLOR) : SV_TARGET
     blend_factor[2] = 0.3f;
     blend_factor[3] = 0.4f;
     ID3D10Device_OMSetBlendState(device, blend_state, blend_factor, D3D10_DEFAULT_SAMPLE_MASK);
+    /* OMGetBlendState() arguments are optional */
+    ID3D10Device_OMGetBlendState(device, NULL, NULL, NULL);
+    ID3D10Device_OMGetBlendState(device, &tmp_blend_state, NULL, NULL);
+    ID3D10BlendState_Release(tmp_blend_state);
+    sample_mask = 0;
+    ID3D10Device_OMGetBlendState(device, NULL, NULL, &sample_mask);
+    ok(sample_mask == D3D10_DEFAULT_SAMPLE_MASK, "Unexpected sample mask %#x.\n", sample_mask);
+    memset(tmp_blend_factor, 0, sizeof(tmp_blend_factor));
+    ID3D10Device_OMGetBlendState(device, NULL, tmp_blend_factor, NULL);
+    ok(tmp_blend_factor[0] == 0.1f && tmp_blend_factor[1] == 0.2f
+            && tmp_blend_factor[2] == 0.3f && tmp_blend_factor[3] == 0.4f,
+            "Got unexpected blend factor {%.8e, %.8e, %.8e, %.8e}.\n",
+            tmp_blend_factor[0], tmp_blend_factor[1], tmp_blend_factor[2], tmp_blend_factor[3]);
+
     ID3D10Device_OMGetBlendState(device, &tmp_blend_state, tmp_blend_factor, &sample_mask);
     ok(tmp_blend_factor[0] == 0.1f && tmp_blend_factor[1] == 0.2f
             && tmp_blend_factor[2] == 0.3f && tmp_blend_factor[3] == 0.4f,
diff --git a/dlls/d3d11/device.c b/dlls/d3d11/device.c
index 8d88ee26222..417638bf314 100644
--- a/dlls/d3d11/device.c
+++ b/dlls/d3d11/device.c
@@ -2190,20 +2190,26 @@ static void STDMETHODCALLTYPE d3d11_device_context_OMGetBlendState(ID3D11DeviceC
     struct d3d11_device_context *context = impl_from_ID3D11DeviceContext1(iface);
     struct wined3d_blend_state *wined3d_state;
     struct d3d_blend_state *blend_state_impl;
+    unsigned int tmp_sample_mask;
+    float tmp_blend_factor[4];
 
     TRACE("iface %p, blend_state %p, blend_factor %p, sample_mask %p.\n",
             iface, blend_state, blend_factor, sample_mask);
 
     wined3d_mutex_lock();
-    if ((wined3d_state = wined3d_device_context_get_blend_state(context->wined3d_context,
-            (struct wined3d_color *)blend_factor, sample_mask)))
+    if (!blend_factor) blend_factor = tmp_blend_factor;
+    if (!sample_mask) sample_mask = &tmp_sample_mask;
+    wined3d_state = wined3d_device_context_get_blend_state(context->wined3d_context,
+            (struct wined3d_color *)blend_factor, sample_mask);
+    if (blend_state)
     {
-        blend_state_impl = wined3d_blend_state_get_parent(wined3d_state);
-        ID3D11BlendState_AddRef(*blend_state = &blend_state_impl->ID3D11BlendState_iface);
-    }
-    else
-    {
-        *blend_state = NULL;
+        if (wined3d_state)
+        {
+            blend_state_impl = wined3d_blend_state_get_parent(wined3d_state);
+            ID3D11BlendState_AddRef(*blend_state = &blend_state_impl->ID3D11BlendState_iface);
+        }
+        else
+            *blend_state = NULL;
     }
     wined3d_mutex_unlock();
 }
@@ -5541,10 +5547,19 @@ static void STDMETHODCALLTYPE d3d10_device_OMGetBlendState(ID3D10Device1 *iface,
     d3d11_device_context_OMGetBlendState(&device->immediate_context.ID3D11DeviceContext1_iface,
             &d3d11_blend_state, blend_factor, sample_mask);
 
+    if (blend_state)
+    {
+        if (d3d11_blend_state)
+        {
+            *blend_state = (ID3D10BlendState *)&impl_from_ID3D11BlendState(d3d11_blend_state)->ID3D10BlendState1_iface;
+            ID3D10BlendState_AddRef(*blend_state);
+        }
+        else
+            *blend_state = NULL;
+    }
+
     if (d3d11_blend_state)
-        *blend_state = (ID3D10BlendState *)&impl_from_ID3D11BlendState(d3d11_blend_state)->ID3D10BlendState1_iface;
-    else
-        *blend_state = NULL;
+        ID3D11BlendState_Release(d3d11_blend_state);
 }
 
 static void STDMETHODCALLTYPE d3d10_device_OMGetDepthStencilState(ID3D10Device1 *iface,
diff --git a/dlls/d3d11/tests/d3d11.c b/dlls/d3d11/tests/d3d11.c
index 553caa10e46..2ed9aed490e 100644
--- a/dlls/d3d11/tests/d3d11.c
+++ b/dlls/d3d11/tests/d3d11.c
@@ -12608,6 +12608,20 @@ static void test_clear_state(void)
     ID3D11DeviceContext_OMGetDepthStencilState(context, &tmp_ds_state, NULL);
     ok(tmp_ds_state == ds_state, "Got unexpected depth stencil state %p, expected %p.\n", tmp_ds_state, ds_state);
     ID3D11DepthStencilState_Release(tmp_ds_state);
+    /* OMGetBlendState() arguments are optional */
+    ID3D11DeviceContext_OMGetBlendState(context, NULL, NULL, NULL);
+    ID3D11DeviceContext_OMGetBlendState(context, &tmp_blend_state, NULL, NULL);
+    ok(tmp_blend_state == blend_state, "Got unexpected blend state %p, expected %p.\n", tmp_blend_state, blend_state);
+    ID3D11BlendState_Release(tmp_blend_state);
+    sample_mask = 0;
+    ID3D11DeviceContext_OMGetBlendState(context, NULL, NULL, &sample_mask);
+    ok(sample_mask == 0xff00ff00, "Got unexpected sample mask %#x.\n", sample_mask);
+    memset(blend_factor, 0, sizeof(blend_factor));
+    ID3D11DeviceContext_OMGetBlendState(context, NULL, blend_factor, NULL);
+    ok(blend_factor[0] == 0.1f && blend_factor[1] == 0.2f
+            && blend_factor[2] == 0.3f && blend_factor[3] == 0.4f,
+            "Got unexpected blend factor {%.8e, %.8e, %.8e, %.8e}.\n",
+            blend_factor[0], blend_factor[1], blend_factor[2], blend_factor[3]);
 
     ID3D11DeviceContext_OMGetRenderTargets(context, D3D11_SIMULTANEOUS_RENDER_TARGET_COUNT, tmp_rtv, &tmp_dsv);
     for (i = 0; i < D3D11_SIMULTANEOUS_RENDER_TARGET_COUNT - 1; ++i)