Background and Aims: As mast cells (MC) serve as a link between mucosal immune activity and the nervous system, it is likely they also play a role in the pathogenesis of irritable bowel syndrome (IBS). This connection might be an important factor in the development of IBS-related symptoms. Method: This overview comprises 36 case-control studies published from 2000 to 2018 that investigated MC in bowel biopsies of IBS patients and controls. The studies were selected from PubMed, EMBASE, Central, SemanticScholar by an electronic search, performed using RISMed R package. Results: Significantly increased mucosal MC counts/or density in IBS patients compared to controls was observed in 30 studies. Five studies reported no differences and only one of the studies found a decreased amount of MC in an IBS patient. Furthermore, 15 studies made a statement regarding the correlation between the amount of MC and IBS associated symptoms. A significant positive correlation between MC count and IBS-associated symptoms was found in six investigations. A negative correlation was not reported. Conclusion: The results support the idea that MC are involved in IBS pathophysiology as key players in the interplay between psychological factors and the frequency and severity of IBS symptoms.