As ill reptiles only show nonspecific clinical signs, blood chemistry parameters are a valuable help in diagnosis. Practicable sites for obtaining blood of snakes, sauria and chelonians are vena coccygealis ventralis and cardiac puncture, of chelonians also vena jugularis, axillaris and coccygealis dorsalis. The following blood parameters were investigated: number of erythrocytes and leucocytes, urea, uric acid, creatinine, AST (GOT), ALT (GPT) GLDH, AP, total bilirubin, CK, LDH, lipase, alpha-amylase, calcium, phosphorus, sodium, potassium, chloride and total protein. Especially for diagnosing nephropathies evaluation of urea and uric acid proved to be valuable.