Background: Promotion of appropriate complementary feeding practices is important in reducing malnutrition in infants and young children. Yet, India has dismal rates of optimal complementary feeding practices which are not rising. Aim: This study aimed to find the impact of the educational intervention directed through peer counselors to promote optimal complementary feeding practices. Methods and materials: This is an Interventional study, which has been conducted in an urban slum of Delhi using multi-stage random sampling. From the study area two sectors were randomly selected. From one sector, 54 pregnant women were selected who were not given any counselling forming the non-intervention group. From the other sector, 159 pregnant women were selected to form the intervention group (Igr) which were further divided into 3 sub-groups; one sub-group was imparted counselling by a nutrition professional (Igr A; n=53) and the other two (Igr B1;n=53 and Igr B2; n=53) by the peer counselors who where the local health workers trained for promoting optimal infant feeding practices. The infants were followed up till their first birthday and in order to study the impact of counseling, the complementary feeding practices of the intervention and the non-intervention groups have been compared Results: In the intervention groups, the prevalence of exclusive breastfeeding at 6 months was significantly higher as compared to the non-intervention group (67.5 % vs. 4.2 %). In the intervention groups, 2.6 per cent infants received semisolid/ solid foods before the age of 6 months, 75.1 percent between 6 - 7 months and the rest by the age of 9 months. However, in the Non-Igr, the respective figures were 48.9, 19.4 and 25.4 per cent; and at the age of one year, 6.4 per cent infants were still being given predominantly mother’s milk. 99.3 per cent infants in the Igrs as compared to 82.3 per cent in the Non-Igr (P<0.05) continued to receive breast milk till the age of 12 months. Conclusions: The promotion of optimal complementary feeding through appropriately trained peer counselors is feasible, although it is can only be achieved through consistent efforts and adequate training/monitoring of such interventions.