A new and efficient method for the preparation of substituted 3,4-dihydropyrimidin-2(1H)-ones via Biginelli synthesis using catalytic amounts of 1,3-dichloro-5,5-dimethylhydantoin is presented. Short reaction times, easy work-up, high yields of products and stability, easy-handling, non-toxicity and cheapness of the catalyst are noteworthy advantages of the present work.