A two-day-old male neonate was inadvertently immunized with 20-times the recommended dose of Bacillus Calmette-Guérin (BCG) vaccine (1.0 ml instead of 0.05 ml). Examination of the neonate after one day revealed no signs of local reaction at the site of injection or systemic manifestation. However, nine days later, he developed a swelling (4 × 3 cm) at the site of injection without any enlargement of the lymph node, pallor, or jaundice. A needle aspiration of the swelling was done and sent for culture. The culture showed the BCG strain only. The infant was not started on antituberculosis medication, due to the absence of symptoms suggestive of systemic disease. There were no other complications up to the age of 18 months. The case highlights the importance of administering the correct dose and using the appropriate technique of the BCG vaccine, and explains the management options to prevent local and systematic complications that may occur due to overdose.