Background: Infantile colic is one of the most common causes of mothers’ referral to physicians and pediatricians for treatment of their infants. This disorder is characterized as unnatural excessive crying which has been mostly observed during the first three months of birth among 8-40% of infants. Cow milk and cow milk formula are the main causes of infantile colic. This study attempts to evaluate the relationship of type of nutrition with the occurrence of infantile colic. Methods: This case-control study was carried out on infants referred to the pediatric clinics throughout Kashan during 2013. One hundred infants with colic were classified as cases and one hundred healthy individuals matched with patients in age and gender, were considered as controls. Parents of the two groups were asked about type of nutrition of their infants. According to the type of nutrition, the infants were included in one of three groups: merely breast-fed, breast-fed and formula-fed and merely formula-fed infants. Correlation of type of nutrition with infantile colic was then determined in the study. Chi-square was used to analyze the data. Results: No significant differences were observed between the two groups in terms of age and gender.69 (69%), 8 (8%), and 23 (23%) of the infants in the case group were breast-fed, breast-fed and formula-fed, and formula-fed, respectively. Whereas in the control group 90 (90%), 8 (8%), and 2 (2%) of the infants were breast-fed, breast-fed and formula-fed, and formula-fed, respectively (P<0.0001). Conclusions: Our study confirmed that the occurrence of infantile colic is associated with formula feeding. In other words, formula-fed infants were at more risk of infantile colic than the others.