Objective: To determine the rate of vitamin B 12 deficiency among exclusively breast fed term infants in central Punjab Method: This descriptive case series included all 120 exclusively breast fed, term, and healthy infants with age range 1-6 months at Children, Hospital, Lahore. The maternal socio-demographic details in addition to infants’ anthropometric measurements were recorded and CBS and serum Vit B12 levels were evaluated by sending the samples to the hospital lab. We used SPSS 16th vesion for data analysis. Results: Mean age of the infants was 3.25+1.47 months. 58.33%(n=70) were male and 41.67%(n=50) were female infants. The mean serum vitamin B12 levels were recorded as 196.81 (±121.432)pg/mL. Frequency of low vitamin B12 (<200 pg/ml)in infants was recorded in Low serum vitamin B12 levels (<200 pg/ml) was seen in 66 (55%) of infants. Conclusion: The rate of vit B12 deficiency is higher in EBF infants and due to its an important role in neurologic development during infancy, it is necessary to address this issue in infants