Neonatal screening is a widely accepted, cost-effective method for early detection of various inborn errors of metabolism. This series of three articles examines different aspects of neonatal screening. In the first article, the author discussed general principles of screening and its function in the spectrum of diagnostic techniques for genetic disease. In this, the second article, the author reviews the history and current practices of neonatal screening in Canada. The individual diseases for which screening is used and particular points of interest for each of these diseases are briefly described. The author also outlines the benefits of screening and treatment. In the final article of this series, the author will examine controversial topics that represent the possible future of screening.