Introduction. Researchers have focused their attention on the role of inflammatory processes in the development and progression of lithogenesis. The new Lithos-system technology has gained significant interest, based on the analysis of morphological model of crystalline and noncrystalline structures in dehydrated biological fluids. With this method, we can determine signs of bacterial and fungal infections, active process of lithogenesis, composition of urine crystals, acute candidiasis of the urinary system, glomerular disorders of kidneys and renal tissue sclerosis. Aim. This study was performed for evaluation microbial adhesion to urothelium in patients with nephrolithiasis. Methods. A drop of buffer solution (pH 7.2) is applied on a glass slide to which a drop of urine containing bacteria and urothelium is added, collected from patients with nephrolithiasis. The preparation is placed in a humid chamber (37◦C, 30 minutes), then dried at the same temperature, fixed with methanol, stained with methylene blue and observed microscopical. Results. In 26 patients with nephrolithiasis, negative adhesion (0-1.0) was detected in 7 patients without urinary infection. In 8 patients, medium adhesion (1-10.0) was detected with E. coli and Pseudomonas infection. In 11 patients with positive adhesion (>10.0), the concomitant infection was formed by Proteus, Klebsiella and staphylococci. Conclusions. The process of microbial adhesion to urothelium is more frequently encountered in the urine of patients with multiple and coral-shaped stones, with Gram-negative infections, Proteus, Klebsiella. The absence of adhesion process correlates with formation of urate and cystine stones. In urine with positive and medium adhesion, the chemical component was struvite.