This work carried out on 515 infants immunized by BCG vaccine in one urban and another rural health center in Kalyoubia governorate to study the adverse events following BCG immunization . Adverse events were observed in 12.6% of the immunized infants. They were in the form of of sepsis (6.4%); scar> 2 cm in diameter (5.4%) and lymphadenitis (0.8%). The observed adverse events were found to be more frequent among rural infants than urban ones (15.5% and 10.9% respectively). Incorrect administration of BCG vaccine was found to be the most important factor inducing these adverse events and it was detected more frequently in rural than urban infants (15.6% and 2.4% respectively). Proper training of the vaccinators, especially in rural health centers, on the correct technique to develop the needed skill is recommended.