BACKGROUND AND OBJECTIVE: Inflammatory bowel disease (IBD) is a polygenic complex trait. The expression and presence in biopsiae from IBD patients points to a putative role of these genes in genetic susceptibility to IBD. This is the first association study on these genes in relation with IBD. PATIENTS AND METHOD: Two polymorphisms were analyzed within F2R/PAR1 and another one mapping to F2RL1/PAR2 in 778 healthy controls and 943 IBD cases (Crohn's disease and ulcerative colitis patients from 2 cohorts from Madrid and Granada). RESULTS: No significant differences in the distribution of the PARs' polymorphisms were found. CONCLUSIONS: There is no evidence of association of the analyzed polymorphisms with IBD risk.