The purpose of this study was to evaluate the applicability of endoscopic examination as a diagnostic method in urethra and bladder ailments in dogs. The experiment involved 60 dogs of different breeds and gender, weighing from 5 to 65 kg, aged between 7 months and 12 years. The dogs were divided into two groups. Group I consisted of clinically healthy animals on which all the lower urinary tract endoscopic examinations described in the literature as well as biopsies of mucosa were performed. Group II consisted of clinical patients, on which endoscopic diagnostic examination was conducted and, on some of them, biopsies for histopathologic examination were made. The results of the experiment suggest that the lower urinary track endoscopy is a suitable diagnostic technique for recognition and differentiation of mucosa inflammation, establishment of causes of haematuria, diagnostics of neoplasms and detection of the existence of an ectopic ureter. Biopsy and histopathologic examination improved the diagnostic value of endoscopy. The techniques tested in our study, inclusive of more invasive method like PPC and cystoscopy on males preceded by the perineal urethrotomy, enable doctors to perform the lower urinary tract endoscopic examination on dogs, especially up to 5 kg. regardless of their gender.