The preparation of thin films of US by chemical bath deposition is mostly based on the utilisation of ammonia as a complexing agent for cadmium ions. Here we report on a new method based on potassium nitrilotriacetate that eliminates the problems of ammonia volatility and toxicity. We prepared high quality films of closely packed nanocrystals with a thickness of up to 300 nm. The radius of the nanocrystals can be tuned from 2.6 to more than 10 nm by post-preparation heat treatment of the as-prepared films.