Objective: To determine the pattern of breastfeeding in infants who conceived by assisted reproductive techniques (ART).

Materials and methods: In a cross-sectional study, 312 infants were selected by the non-random consecutive method from ART infants who referred by Royan institute to Child Health Research Department. Infants were born between Septembers 2007and September 2009 in Tehran. Infant nutrition, mother age, ART techniques, birth growth indexes, beginning time and the kind of nutrition and growth pattern until 6 months were considered.

Results: Breastfed infants were 110(35.2%), 46(14.7%) ones were formula fed and 156(50%) were both. The rate of breastfeeding on the first day after birth in neonates with the low birth weight were less than normal birth weight ones .Approximately 36.8% of infants who had normal increase of weight and height till 6 months, began feeding on the first day of life. Mothers' age and ART technique did not affect the beginning time and kind of infants feeding.

Conclusion: The most important factor which affects ART infants' nutrition pattern is their birth weight. The beginning time of feeding affects their weight and length increase till 6 months. Based on reproductive techniques, breastfeeding was similar in different methods of ART.