Abstract Background Early-onset inflammatory bowel disease (IBD) is classified into Crohn’s disease (CD), ulcerative colitis (UC) and unclassified disorders, which has a chronic, relapsing course and can result in substantial long-term morbidity. IBD is a multifactorial disorder with genetic susceptibility, immunological predisposition and environmental triggers. The objective of this study was to generally determine the prevalence of IL10R mutation in IBD patients in Isfahan, Iran. We performed sequencing of all exons in IL10RA and IL10RB in a cohort of IBD patients and healthy controls. Methods Total DNA contents of 76 patients and 50 healthy controls were extracted from whole blood and polymerase chain reaction (PCR) amplifications and sequencing of whole exons in IL10R were performed. Results Overall, we determined 13 single nucleotide polymorphisms (SNPs) in all IL10R genes. Of them, rs3135932 and rs2229113 of the IL10RA1 gene, in exons 4 and 7, respectively, were significantly associated with IBD occurrence in patients. Conclusions Our results also confirmed that early-onset IBD could be attributed to a synergistic effect of several variant alleles of the genes encoding IL10 receptors. These variants, alone, could only give rise to a sub-clinical manifestation of IBD.