Does the 2005 Toyota Prius have a timing belt or chain?

The 2005 Toyota Prius uses a timing chain instead of a timing belt. In fact all Prius versions and years use the chain instead of the belt. The chain should last for the life of the vehicle unlike the belt which needs to be replaced every 60,000 to 100,000 miles. It tends to last for the life of the vehicle because it is on the inside of the engine and gets help from engine oil and the belt doesn't because it is on the outside of the engine and is exposed. Even though You shouldn't need to replace the timing chain You should still inspect it every 150,000 miles just in-case something went wrong with it. You can inspect it by removing the valve cover and looking at the tension.