Aim — to determine optimal time of biliary tract decompression and bile reinfusion into gastrointestinal tract in patients with malignant obstructive jaundice. Material and methods. 179 medical records of patients with obstructive jaundice were analyzed in order to identify risk factors of postoperative complications. Prospective trial included bile examination in 34 patients with malignant obstructive jaundice. The new algorithm of preoperative preparation of patients was proposed using these data. Results. Preoperative hyperbilirubinemia over 50 μmol/l before radical surgery and over 80 μmol/l before palliative surgery is followed by increase of postoperative morbidity from 42.1 to 66.7% and from 11.1 to 37.5%, respectively. The concentration of AST and ALT approaches the norm in 13.63±2.39 days after decompression. Five-day period after external drainage is characterized by the same level of overall bilirubin in the bile while bile reinfusion into gastrointestinal tract after 1—2 days leads to advanced symptoms of intoxication. The proposed tactics allows to reduce postoperative morbidity from 36.9 to 26.5% (p<0.05) and mortality from 5.5 to 2.9%, respectively (p<0.05). Conclusion. Duration of biliary decompression should be at least 13.63±2.39 days to reduce postoperative morbidity and mortality. Bile reinfusion into gastrointestinal tract should be started in 5—6 days after decompression.