This cluster-randomized interventional trial at peri-urban settings of Karachi was conducted to evaluate the impact of maternal educational messages regarding appropriate complementary feeding (CF) on the nutritional status of their infants after 30 weeks of educational interventions delivered by trained community health workers. Mothers in the intervention group received three education modules about breastfeeding (BF) and appropriate CF at a baseline visit and two subsequent visits 10 weeks apart. The control group received advice about BF according to national guidelines. Infants' growth [weight, length, and mid-upper arm-circumference (MUAC), stunting, wasting, and underweight] were measured at four time points. At the end of the study, infants in the intervention group had a higher mean weight of 350 g (p=0.001); length of 0.66 cm (p=0.001), and MUAC of 0.46 cm (p=0.002) compared to the controls; proportionate reduction of stunting and underweight were 10% (84% vs 74%; ORadj 8.36 (5.6-12.42) and 5% (25% vs 20%; ORadj 0.75 (0.4-1.79) in the intervention compared to the control group. For relatively food-secure populations, educational interventions about appropriate CF to mothers had a direct positive impact on linear growth of their infants.