The authors provide the information necessary so that nurses are capable of adequately carrying out the duties which pertain to neonatal screening programs for hereditary metabolic diseases. The authors briefly describe those diseases which are subject to neonatal screening with the objective of providing their basic features, especially in relation to neonatal screening and the benefits which this may provide. The authors explain the method to correctly take a blood sample on the paper filter sample cards and they describe the most frequently committed errors as a way to prepare nursing personnel which may at some time have contact with these functions so that these are properly performed.