Objective: This study aimed to evaluate the knowledge, attitude, and practices of parents about breastfeeding, complementary food, and infant nutrition who have healthy infants born at term and under 2 years of age. Materials and Methods: This is a cross-sectional study conducted among the parents of infants who came for well-child visits to pediatric clinics of 4 hospitals. Healthy infants under 2 years of age and who had been born at term were interviewed. The questionnaire included 35 questions to evaluate parents’ knowledge, attitude, and practices about breastfeeding and infant nutrition in addition to sociodemographic data. Data were obtained via questionnaire and were analyzed using Statistical Package for the Social Sciences 20.0 package program. Results: The study group consisted of 679 infants and their parents. The median durations of exclusive breastfeeding and total breastfeeding time were found to be 4 months and 10 months. Although 75% of the participants stated that infants must be exclusively breastfed for 6 months, the rate of exclusive breastfeeding for the first 6 months was 44%. The 393 (58%) participants used formula for infant nutrition and 47 (12%) of those started with complementary feeding. 90% of the participants stated that formula advertisements did not affect their decision on starting formula but the rate of thinking that other people may be affected by the advertisements was 80%. Conclusion: The knowledge of parents on human milk is not insufficient but they need to be supported especially to continue exclusive breastfeeding during the first 6 months and appropriate complementary food during the weaning period.