A complex system of chemical investigation of urinary concrements has been developed. Qualitative analysis methods have been improved so that conclusions about urinary calculus composition are based on the data of objective chemical reactions specific for this or that component. This makes the conclusion highly reliable. Simple photometric methods are suggested for measurements of phosphate and oxalate ions in concrements of a mixed composition. These methods permit a quantitative analysis of stones with a very little mass and even as small as sand particles. The results permit assessment of oxalate to phosphate ratio and help detect the predominance of this or that component, thus allowing the physician to recommend well-grounded measures to prevent urolithiasis recurrences. The methods were tried at the Central Clinicodiagnostic Laboratory of District Clinical Hospital in Ivanovo: more than 220 samples were analyzed there. The methods were approved. The methods are simple and available, this recommending their wide use at inpatient and outpatient clinics.