Rubber toughened polymer blends is an important theme in the history of polymer science and engineering. Rubber toughening of semi-crystalline polymers (e.g., nylon 6) has seen significant progress since late 1970s. This presentation will summarize the developments of rubber-toughened polyamides particularly the role of matrix crystalline structure/crystallinity. Apart from rubber toughening, future vision on some of polymer blends systems will be discussed, including nanostructured polymer blends, rubber toughened nanocomposites, and biodegradable polymer blends.