The aim of our study was to compare patients with irritable bowel syndrome (IBS) and healthy controls regarding the expression of toll-like receptors 2, 4, 5, and 9 (TLR2, TLR4, TLR5, and TLR9), the primary mucosal receptors of bacterial components, in small and large bowel mucosa. Methods. We analysed biopsies from jejunum and sigmoid colon of 22 patients (17 females) with IBS aged 18–66 (median: 39) years and 14 healthy volunteers (12 females) aged 22–61 (median: 42) years. Here, TLR4 is linked to irritable bowel syndrome.