Routine neonatal circumcision has long been controversial. Presented here is a cost-effectiveness analysis of the consequences of the treatment choices (circumcision versus no circumcision) using a decision tree model. For a simulated 85-year life expectancy, routine neonatal circumcision had an expected lifetime cost of $164.61 per patient circumcised and a quality-adjusted survival of 84.999 years. Conversely, for the noncircumcision approach, the expected average lifetime cost was $139.26 per patient, and the quality-adjusted survival was 84.971 years. The net cost-effectiveness ($919.87 per quality-adjusted life year) is within the range usually considered worthwhile for public health policy. However, because of the minor differences in lifetime cost ($25) and benefit (10 days of life) for an individual and the tenuous values available for disease incidence and surgical risk, we conclude that there is no medical indication for or against circumcision. Additional analyses suggested that reported benefits in preventing penile cancer and infant urinary tract infections are insignificant compared to the surgical risks of post neonatal circumcision. The decision regarding circumcision may most reasonably be made on nonmedical factors such as parent preference or religious convictions.