diff --git a/layout/style/nsCSSPropList.h b/layout/style/nsCSSPropList.h
index 98ffaf8160b..ea5788c3a7c 100644
--- a/layout/style/nsCSSPropList.h
+++ b/layout/style/nsCSSPropList.h
@@ -1980,7 +1980,7 @@ CSS_PROP_POSITION(
         CSS_PROPERTY_VALUE_NONNEGATIVE |
         CSS_PROPERTY_STORES_CALC,
     "",
-    VARIANT_HLP | VARIANT_CALC,
+    VARIANT_AHLP | VARIANT_CALC,
     nsnull,
     offsetof(nsStylePosition, mMinHeight),
     eStyleAnimType_Coord)
@@ -1992,7 +1992,7 @@ CSS_PROP_POSITION(
         CSS_PROPERTY_VALUE_NONNEGATIVE |
         CSS_PROPERTY_STORES_CALC,
     "",
-    VARIANT_HKLP | VARIANT_CALC,
+    VARIANT_AHKLP | VARIANT_CALC,
     kWidthKTable,
     offsetof(nsStylePosition, mMinWidth),
     eStyleAnimType_Coord)
diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index 066842780ae..a5839ad4220 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -6383,7 +6383,7 @@ nsRuleNode::ComputePositionData(void* aStartStruct,
            SETCOORD_LPAEH | SETCOORD_INITIAL_AUTO | SETCOORD_STORE_CALC,
            aContext, mPresContext, canStoreInRuleTree);
   SetCoord(*aRuleData->ValueForMinWidth(), pos->mMinWidth, parentPos->mMinWidth,
-           SETCOORD_LPEH | SETCOORD_INITIAL_ZERO | SETCOORD_STORE_CALC,
+           SETCOORD_LPAEH | SETCOORD_INITIAL_AUTO | SETCOORD_STORE_CALC,
            aContext, mPresContext, canStoreInRuleTree);
   SetCoord(*aRuleData->ValueForMaxWidth(), pos->mMaxWidth, parentPos->mMaxWidth,
            SETCOORD_LPOEH | SETCOORD_INITIAL_NONE | SETCOORD_STORE_CALC,
@@ -6393,12 +6393,21 @@ nsRuleNode::ComputePositionData(void* aStartStruct,
            SETCOORD_LPAH | SETCOORD_INITIAL_AUTO | SETCOORD_STORE_CALC,
            aContext, mPresContext, canStoreInRuleTree);
   SetCoord(*aRuleData->ValueForMinHeight(), pos->mMinHeight, parentPos->mMinHeight,
-           SETCOORD_LPH | SETCOORD_INITIAL_ZERO | SETCOORD_STORE_CALC,
+           SETCOORD_LPAH | SETCOORD_INITIAL_AUTO | SETCOORD_STORE_CALC,
            aContext, mPresContext, canStoreInRuleTree);
   SetCoord(*aRuleData->ValueForMaxHeight(), pos->mMaxHeight, parentPos->mMaxHeight,
            SETCOORD_LPOH | SETCOORD_INITIAL_NONE | SETCOORD_STORE_CALC,
            aContext, mPresContext, canStoreInRuleTree);
 
+
+  // Handle 'auto' values for min-width / min-height
+  if (pos->mMinWidth.GetUnit() == eStyleUnit_Auto) {
+    pos->mMinWidth.SetCoordValue(0);
+  }
+  if (pos->mMinHeight.GetUnit() == eStyleUnit_Auto) {
+    pos->mMinHeight.SetCoordValue(0);
+  }
+
   // box-sizing: enum, inherit, initial
   SetDiscrete(*aRuleData->ValueForBoxSizing(),
               pos->mBoxSizing, canStoreInRuleTree,
diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index 5a4d0c4fcb0..515c2d0ffd5 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -2352,7 +2352,7 @@ var gCSSProperties = {
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
 		prerequisites: { "display": "block" },
-		initial_values: [ "0", "-moz-calc(0em)", "-moz-calc(-2px)", "-moz-calc(-1%)" ],
+		initial_values: [ "auto", "0", "-moz-calc(0em)", "-moz-calc(-2px)", "-moz-calc(-1%)" ],
 		other_values: [ "30px", "50%",
 			"-moz-calc(2px)",
 			"-moz-calc(50%)",
@@ -2360,14 +2360,14 @@ var gCSSProperties = {
 			"-moz-calc(25px*3)",
 			"-moz-calc(3*25px + 50%)",
 		],
-		invalid_values: [ "auto", "none", "-moz-max-content", "-moz-min-content", "-moz-fit-content", "-moz-available" ]
+		invalid_values: [ "none", "-moz-max-content", "-moz-min-content", "-moz-fit-content", "-moz-available" ]
 	},
 	"min-width": {
 		domProp: "minWidth",
 		inherited: false,
 		type: CSS_TYPE_LONGHAND,
 		prerequisites: { "display": "block" },
-		initial_values: [ "0", "-moz-calc(0em)", "-moz-calc(-2px)", "-moz-calc(-1%)" ],
+		initial_values: [ "auto", "0", "-moz-calc(0em)", "-moz-calc(-2px)", "-moz-calc(-1%)" ],
 		other_values: [ "30px", "50%", "-moz-max-content", "-moz-min-content", "-moz-fit-content", "-moz-available",
 			"-moz-calc(2px)",
 			"-moz-calc(50%)",
@@ -2375,7 +2375,7 @@ var gCSSProperties = {
 			"-moz-calc(25px*3)",
 			"-moz-calc(3*25px + 50%)",
 		],
-		invalid_values: [ "auto", "none" ]
+		invalid_values: [ "none" ]
 	},
 	"opacity": {
 		domProp: "opacity",