Background: Trichinella spiralis(T. spiralis) is a zoonotic nematode and food borne parasite. The intestinal phase is critical for trichinellosis as it determines both process and consequences of the disease. T. spiralis-induced mucosal mast cells (MMCs) hyperplasia in the small intestine may contribute to expulsion of adult worms. CD117 marker (C-kit) which is expressed by mast cells (MC) as well as a variety of neoplasms is considered a better marker for mast cell populations. Objective: Our aim was to clarify the contribution of MMCs in the effector phase of the immune response to intestinal phase of T.spiralis during the course of infection in mice. Material and Methods: MMCs hyperplasia reaction was investigated in the intestine of mice infected with T. spiralis by immunohistochemical study using CD117 marker and analysis of results by ImageJ software. Results: The results showed that MMCs continued to increase until 14 days post infection (dpi), coinciding with time of worm expulsion; and started to decline afterward. The minimal number of MMCs was detected 35dpi. Conclusion: Our findings suggest that T. spiralis infection causes a series of pathological and time-associated changes within intestinal immune cell populations in infected mice during the intestinal phase. MMCs hyperplasia is a clear contributor to the worm expulsion