Tuberculosis is an important health problem in developing countries and the BCG vaccine plays an important part in preventing the disease. There are different reports about the preventive value of BCG. Some of them claim that it is satisfactory while others suggest that it provides little protection. There are also varying ideas about the optimum time to vaccinate babies, some studies suggesting that late vaccination confers a high degree of protection. This prospective controlled study has been undertaken to evaluate the value of BCG vaccine given to babies during their first three days of life versus its value when given in their third month of life. Evaluation was measured by the results of tests with purified protein derivative (PPD), by vaccine scars, and by the complications of the vaccine. It was found that BCG given at the end of the third month provides a higher rate of response and fewer complications than when given during the first three days of life.