Seven samples of renal calculi were analysed, which have been collected from patients in area of Zagreb and Osijek. Methods used for their analysis include X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD results show the chemical composition of individual sample, and microscopic methods (SEM, AFM) are used to observe their morfological features. With SEM images individual compounds are observed and explained, including crystal habit, texture and structure of calculus. AFM images indicate different characteristics of crystal growth and the presence of surface nuclei. The composition of every sample is different. Mineral compounds in the samples include calcium oxalate (whewellite, weddellite), phosphate (brushite, hidroxiapatite, struvite), urate and cistine.