Kathmandu valley. Methods The study was based on primary data collected by applying the 30 cluster sampling method. Target populations of the study were young children aged 0-24 months. Interview was taken with the mothers of the children. A set of questionnaire was used for interview of the respondents 150 households. Anthropometric assessment focus group discussion, twenty-four hours dietary recalls, nutrient analysis of the complementary foods and market survey were adopted as a research methodology for data collection. Results Finding of the study indicated that traditional about 92 percent households were found practicing traditionally complementary feeding practices (TCFP) were 8 percent households were found practicing commercial Complementary Feeding Practicing (CCFP). Traditional complementary foods given to the children were found lacking in macronutrient carbohydrate and protein severely, therefore, not fulfilling the nutritional requirement of the children. Among traditional complementary food fed children, 63 percent of children were found suffering from mild to severe from of malnutrition where as among commercial food fed, only 41 percent of children were found suffering from such form of malnutrition. About 33 percent of the children suffering from severe malnutrition were come from the household of employees. Children from Newar ethnicity of Lalitpur district were found more suffering from severe type of malnutrition compared to other ethnic groups. In addition baby boys were found suffering more from severe type of malnutrition compared to baby girls. Conclusion Nutritional status of children from Kathmandu district found better compared to young children from other district. Children from Lalitpur district were found more severely malnourished. Surprisingly baby boys found more severely malnourished compared to baby girls. Traditional foods fed children were found more severely malnourished compared to commercial complementary food fed. Finding of this study clearly indicated that complementary feeding practices have direct impact on nutritional status of young children.