diff --git a/src/components/main/layout/block.rs b/src/components/main/layout/block.rs
index 6057a7a20bf4..d5a98390eda2 100644
--- a/src/components/main/layout/block.rs
+++ b/src/components/main/layout/block.rs
@@ -12,6 +12,8 @@ use layout::inline::InlineLayout;
 use layout::model::{MaybeAuto, Specified, Auto};
 use layout::float_context::FloatContext;
 
+use newcss::values::{CSSClearNone, CSSClearLeft, CSSClearRight, CSSClearBoth};
+use layout::float_context::{ClearLeft, ClearRight, ClearBoth};
 use std::cell::Cell;
 use geom::point::Point2D;
 use geom::rect::Rect;
@@ -249,13 +251,28 @@ impl BlockFlowData {
 
     pub fn assign_height_block(@mut self, ctx: &mut LayoutContext) {
         let mut cur_y = Au(0);
+        let mut clearance = Au(0);
         let mut top_offset = Au(0);
         let mut bottom_offset = Au(0);
         let mut left_offset = Au(0);
 
         for self.box.iter().advance |&box| {
+            let style = box.style();
+            let clear = match style.clear() {
+                CSSClearNone => None,
+                CSSClearLeft => Some(ClearLeft),
+                CSSClearRight => Some(ClearRight),
+                CSSClearBoth => Some(ClearBoth)
+            };
+            clearance = match clear {
+                None => Au(0),
+                Some(clear) => {
+                    self.common.floats_in.clearance(clear)
+                }
+            };
+
             do box.with_model |model| {
-                top_offset = model.margin.top + model.border.top + model.padding.top;
+                top_offset = clearance + model.margin.top + model.border.top + model.padding.top;
                 cur_y = cur_y + top_offset;
                 bottom_offset = model.margin.bottom + model.border.bottom + model.padding.bottom;
                 left_offset = model.offset();
@@ -308,13 +325,13 @@ impl BlockFlowData {
         self.box.map(|&box| {
             do box.with_mut_base |base| {
                 //The associated box is the border box of this flow
-                base.position.origin.y = base.model.margin.top;
+                base.position.origin.y = clearance + base.model.margin.top;
 
                 noncontent_height = base.model.padding.top + base.model.padding.bottom +
                     base.model.border.top + base.model.border.bottom;
                 base.position.size.height = height + noncontent_height;
 
-                noncontent_height = noncontent_height + base.model.margin.top + base.model.margin.bottom;
+                noncontent_height = noncontent_height + clearance + base.model.margin.top + base.model.margin.bottom;
             }
         });
 
diff --git a/src/components/main/layout/float_context.rs b/src/components/main/layout/float_context.rs
index 04c7040acc07..5528d5ae8f73 100644
--- a/src/components/main/layout/float_context.rs
+++ b/src/components/main/layout/float_context.rs
@@ -15,6 +15,12 @@ pub enum FloatType{
     FloatRight
 }
 
+pub enum ClearType {
+    ClearLeft,
+    ClearRight,
+    ClearBoth
+}
+
 struct FloatContextBase{
     float_data: ~[Option<FloatData>],
     floats_used: uint,
@@ -108,6 +114,13 @@ impl FloatContext {
             base.last_float_pos()
         }
     }
+
+    #[inline(always)]
+    pub fn clearance(&self, clear: ClearType) -> Au {
+        do self.with_base |base| {
+            base.clearance(clear)
+        }
+    }
 }
 
 impl FloatContextBase{
@@ -343,5 +356,27 @@ impl FloatContextBase{
             }
         }
     }
+
+    fn clearance(&self, clear: ClearType) -> Au {
+        let mut clearance = Au(0);
+        for self.float_data.iter().advance |float| {
+            match *float {
+                None => (),
+                Some(f_data) => {
+                    match (clear, f_data.f_type) {
+                        (ClearLeft, FloatLeft) |
+                        (ClearRight, FloatRight) |
+                        (ClearBoth, _) => {
+                            clearance = max(
+                                clearance,
+                                self.offset.y + f_data.bounds.origin.y + f_data.bounds.size.height);
+                        }
+                        _ => ()
+                    }
+                }
+            }
+        }
+        clearance
+    }
 }
 
diff --git a/src/test/html/test_clear.html b/src/test/html/test_clear.html
new file mode 100644
index 000000000000..a9b4ae052b94
--- /dev/null
+++ b/src/test/html/test_clear.html
@@ -0,0 +1,48 @@
+<html>
+<head>
+<style>
+#container {
+    width: 300px;
+}
+#left {
+    float: left;
+    width: 100px;
+    height: 100px;
+    background: red;
+}
+#right {
+    float: right;
+    width: 100px;
+    height: 200px;
+    background: blue;
+}
+#clear1 {
+    clear: none;
+    width: 200px;
+    height: 50px;
+    background: green;
+}
+#clear2 {
+    clear: left;
+    width: 200px;
+    height: 50px;
+    background: green;
+}
+#clear3 {
+    clear: right;
+    width: 200px;
+    height: 50px;
+    background: green;
+}
+</style>
+</head>
+<body>
+<div id="container">
+<div id="left"></div>
+<div id="right"></div>
+<div id="clear1"></div>
+<div id="clear2"></div>
+<div id="clear3"></div>
+</div>
+</body>
+</html>