Nowadays, one of the most common groups of diseases in veterinary medicine is the urinary system pathology. Urolithiasis is widespread disease, could be found in many species, including cats, dogs, rabbits, guinea-pigs, turtles etc. Despite the large scale of this pathology in animal world, there are some challenges with diagnostic process and diagnosis’s verification. The aim of our study is estimation of diagnostic value of advanced urine tesiocrystalloscopy in urolithiasis (by the example of cats). We studied crystallogenic and initiated properties of 24 healthy cats and 32 animals with urolithiasis. Own and initiated crystallogenesis of the urine specimens was studied. For teziographic test we used sodium chloride solution (0.45%, 0.9%, 3% consequently), hydrochloric acid solution (0.1H) and sodium hydroxide (0.1H) as a crystal-forming substances. We used the original criterions to estimate crystalloscopic and tezigraphic facias. As the main parameters structure index (SI), crystallizability (Cr), facia's destruction degree (FDD) and edge belt intensity (EB) were used to describe free crystallogenesis, and main tezigraphic coefficient (Q), belt coefficient (B) and FDD were used for the comparative tezigraphy data. Results showed that Cat’s urine in normal conditions has moderate crystallogenic activity, but in urolithiasis it acquires high level of crystallizing, with intermedium value of structure index, and significant destruction of crystal-forming elements. A similar changes of physical-chemical biomedium properties are detected during analysis of tezigraphic microslides of urines of cats with urolithiasis, that was prepared using 0.9% sodium chloride as basis substance. In conclusion, we fixed that tesiocristalloscopic „pattern“ of cats’ urine in urolithiasis significantly transforms into activation of crystal formation and increasing of biomedium’s initiating potential. So, the investigation of free or initialized urine crystallization in urolithiasis has diagnostic value.