BACKGROUND Fatty acids (FA) and their metabolites are closely related to some mechanisms involved in the development of uronephrolithiasis. The aim of this study was to evaluate the relationship between FA composition and type of kidney stones. MATERIAL AND METHODS Abdominal adipose tissue fatty acid methyl esters of 71 men with nephrolithiasis were identified by GC/MS, and the type of kidney stones was identified using FTIR infrared spectroscopy. Patients were divided into groups according to diagnosis of metabolic syndrome (MS) and type of kidney stone. The composition of FA was compared within different groups of patients with different types of kidney stones and between the patients and healthy individuals (control group) (n=100). RESULTS Individuals with nephrolithiasis had a significantly higher level of monounsaturated fatty acids (MUFA) and a lower level of polyunsaturated fatty acids (PUFA) versus healthy individuals. Patients with MS had a higher level of 18: 1ω9 and a lower level of 16: 1ω7 than patients without MS. Individuals with nephrolithiasis, but without MS, had a higher level of saturated fatty acids (SFA) compared to controls. The level of PUFA was higher in the control group (p<0.0001) compared to individuals with uronephrolithiasis, with or without MS. PUFA, ω - 6 PUFA, and 18: 2ω6 were higher in patients with calcium-based kidney stones without MS versus patients with uric acid kidney stones with MS. CONCLUSIONS The levels of MUFA were significantly higher and the levels of PUFA were significantly lower in patients with uronephrolithiasis compared to controls.