Genetically determined features of the xenobiotic biotransformation system play an important role in the development of acute pancreatitis (AP) and its complications. The aim of this study was to assess the contribution of 3 SNPs (CYP1A1 -462 T>C rs1048943, CYP2E1 -1293 G>C rs3813867 and ABCB1 -3435 G>A rs1045642) to the development of AP and its complications. DNA samples were collected from 547 unrelated patients with AP (154 women and 393 men; mean age 48.9 ± 13.1 years) undergoing therapy at surgery departments of Kursk and 573 unrelated individuals without gastrointestinal diseases (161 women and 412 men; mean age 47.8 ± 12.1 years). The polymorphisms were genotyped by PCR using TaqMan probes for allele discrimination. Infected pancreatic necrosis (IPN) was observed in 97 patients; 101 patients developed a pseudocyst (PC); 111 patients had a peripancreatic necrosis (PN). AP was the most common in the carriers of the А allele in ABCB1 G>A (rs1045642) (p = 0.0008). The carriers of the G/G genotype rarely developed both AP (p = 5·10^–4) and its complications: IPN (p = 0.03^R), PN (p = 0.036^R), PC (p = 0.04^R). The carriers of the G/C–C/C CYP2E1 G>C (rs3813867) genotypes who had no long-term history of alcohol abuse rarely developed AP (p = 0.03). The carriers of the G/C CYP2E1 (rs3813867) genotype tended to develop pseudocysts (p = 0.05OD). AP was more frequently complicated by IPN (p = 0.009^R), PN (p = 0.003^R) and PC (p = 0.003^D) in the carriers of the C/C CYP1A1 T>C (rs1048943) genotype. A milder course of AP was typical for the carriers of the G/G ABCB1 G>A (rs1045642) genotype; a more severe course was characteristic of the carriers of the C/C CYP1A1 T>C (rs1048943) genotype.