Introduction: Breastfeeding, along with milk formula and initiation of complementary food, are important factors in early growth and development of children. Despite all well known advantages of breastfeeding, is becoming the usage of milk formula something normal and everyday habit in countries around the world, probably because the lack of knowledge and education. Health-care workers are the one in charge and responsible for informing pregnant women about meaning of breastfeeding and integrate her in health-care education programs for encouraging breastfeeding. Purpose: The purpose of this research is to find out which factors influence the feeding of infants with formula milk. Methods: To conduct the diploma thesis we have chosen descriptive quantitative methods, since we have included survey questionnaire as method of data gathering. The research proceeded from 17. December 2016 to 17. January 2017. Mothers, that were invited to participate, had a child at the age up to two. Data gathering was performed with web page EnKlikAnketa and the analysis of the measurments in program Microsoft Office Excel. Results: There were 259 mothers feeding their children with milk formula and participating in a research. Most of mothers started to use the formula because of the health issues, more comfortable feeding in the public and mostly because of easy, fast and useful way of feeding. Mothers got most of the information about feeding in the internet, health-care fliers, paediatrician, midwife and in school for parents. Majority didn't get enough information about milk formula from health-care workers. Based on health condition of child, the structure of milk formula, accessibility in stores, brand and price of the formula they have decided which one is the most appropriate. Discussion and conclusion: Researches, not only in our country but also in other countries, have shown that mothers are feeding their infants with formula milk very often. The lack of research in this field is reason for too little information about possibilities of infant feeding, usage of milk formulas and reasons for it. Result of research have shown that even more education of (future) parents is needed. There is necessary to introduce and familiarize expectant mothers and fathers with the advantages of breastfeeding, help them and offer the emotional support.