Aim: The aim of this study was conducted to estimate the prevalence of anemia in exclusively breastfed babies between 3-6 months of age. Material and methods: This retrospective observational study was done the Department of Paediatrics, Anugrah Narayan Magadh Medical College and Hospital, Gaya, Bihar, India, from July 2016 to feb 2017. Exclusive breastfed term infants aged between 3-6 months of age (90 days to 180 days) who undergone complete blood count (CBC) examination for some minor ailments was included in this study. All the infants were looked for anemia and its severity. Results: Among 120 infants, 75 were males and 45 were females. According to age 38, 52 and 30 babies were belonging to 3-4, 4-5 and 5-6 months respectively. Mean age was 4.6 month and Hb was 9.8 mg/dl. Median Hb was 9.7 mg/dl. A total of 100 children had anemia as per WHO criteria of <11 gm% of Hb, giving a prevalence of anemia of 83.33%. However if we take 10.5 mg% as cut off value 92 (76.67%) had anemia and for 10 mg%, 74 (61.67%) had anemia. Out of 100, 33 (86.64%) babies with age of 3-4 months, 44 (84.62%) aged 4-5 months and 23 (76.67%) aged 5-6 months had anemia. Segregating by gender, 70 males 93.33% and 30 females 66.67% were anemic. it was found that 73 had mild, 23 had moderate and 4 had severe anemia. Conclusion: breastfed infants between 3-6 months are at increased risk of anemia. Therefore infants after 3 months should be evaluated for anemia and iron deficiency which is the commonest cause of anemia. Such infants should be supplemented with oral iron in addition to exclusive breast feeding for 6 months, to prevent adverse effects of IDA on infants’ growth and development.