The I-STAT Portable Clinical Analyzer was evaluated for its accuracy, reliability, and usefulness in veterinary practice. The values of quality control were verified for accuracy and precision. Venous blood samples of 101 canine patients were analyzed by the i-STAT Portable Clinical Analyzer (Cartridge EC8+) and simultaneously on reference analyzers. The cartridge EC8+ measures pCO(2), pH, sodium, potassium, chloride, haematocrit, glucose and urea. Based on those parameters HCO3- BEecf, haemoglobin are calculated. The results obtained with the I-STAT analyzer correlated very well with those of the reference analyzers except for sodium and chloride. The values of the I-STAT Portable Clinical Analyzer were too high for sodium and chloride. The average overestimation was 5 and 9 mmol/l, respectively. The i-STAT Portable Clinical Analyzer is predestinated for the veterinary practice by performing accurate and reliable values. An analyzing time of only 2.5 minutes, the easy handling as well as low maintenance will make it to a useful setting. It proofed to be economical especially when examining few samples a week.