INTRODUCTION: Despite the technical advance in medicine and the use of minimally invasive laparoscopic techniques, complications of cholecystectomy considerably reduce the quality of life of the operated patients. Development of the most common and severe complication fatty liver disease (FLD) is difficult to predict due to numerous factors that influence its formation.
 AIM: To identify prognostic criteria of formation of FLD in the long-term period after cholecystectomy and to scientifically substantiate their significance.
 MATERIALS AND METHODS: To identify prognostic criteria of formation of FLD in the long-term period after minimally invasive cholecystectomy, 330 patients (159 men and 171 women) who underwent surgical treatment, were examined. Anthropometric data, hemodynamic parameters were evaluated, autonomic index was calculated. US evaluation of choledoch and Elastography of the liver, magnetic resonance tomography of the liver and magnetic resonance cholangiopancreatography were performed. Using chromatography-mass-spectrometry, microbial markers of parietal microbiome of the intestine were determined.
 RESULTS: Parameters of body mass index indicate the interrelation between the formation of FLD and increased body mass in patients of older age. In the first group with FLD, sympathetic status prevailed, and in the control group of the same age, parasympathicotonia was predominating. At the older age, in the second and third subgroup, the autonomic regulation did not influence the formation of FLD. The choledoch diameter in men and women with FLD of the first age subgroup was greater relative to patients of the control group and of the preoperative period and also relative to older patients of the same group. In the long-term period after cholecystectomy in the group with fatty liver disease, the opportunistic microflora prevailed over essential one, and aerobic microflora over anaerobic one. Besides, increased amount of fungi and viruses was noted, as well as a change in the distribution of obligate microflora due to decrease in the content of eubacteria and predomination of lactobacteria over bifidobacteria in the parietal layer of the intestine. In the individuals of older age, reduction of the obligate and increase in the opportunistic microflora including aerobic one, was noted.
 CONCLUSIONS: Age, autonomic regulation and body mass have a significant influence on the formation of FLD in the long-term period after cholecystectomy. In the group of older patients, the influence of the autonomic regulation is lower, and increase in body mass is higher than in younger individuals.