Objective: Despite numerous reports on the effects of meal frequency on biochemical parameters such as plasma lipid profile, glucose and insulin, there is almost no study to investigate the influence of meal frequency on immune system. In the present article, for the first time, the effect of meal frequency on complement components C3 and C4, as key components of the complement system, has been investigated. Materials and Methods: The subjects of this study were fifteen healthy nonsmoker males aged 27.4±6 years. All subjects were placed on two identical diets, in which they consumed the same food either as nine snacks at 2 hrs intervals (nibbling diet) or three meals at 7 hrs intervals (gorging diet). Each diet was continued for fourteen days. At the end of each program, a fasting blood sample was obtained and its complements C3 and C4 levels were determined. The results were compared using Student’s paired t-test.Results: Nibbling diet led to a significant (P<0.05) decrease in the complement C3 level compared to the normal dietary regimen (111.6±34.5vs. 140.0±27.5 mg/dl). On the other hand, during gorging period, no significant change was observed in complement C3 level compared with the control value 145.7±51.5vs. 140.0±27.5 mg/dl). However, the level of complement C4 increased significantly (P< 0.05) following gorging diet (25.6 ±15.5 vs. 37.6±11.5 mg/dl).Conclusion: According to the results obtained, a change in the number of meals may alter the serum levels of complements C3 and C4 with a decrease in both complements levels and an increase in C4 level during nibbling and gorging dietary regimens, respectively.