Mexican axolotls (Ambystoma mexicanum) are used as research animals in a variety of fields, and are also kept as pets. However, there are limited clinical pathology references available for Mexican axolotls that can be used to interpret cases with clinical disease. To establish plasma biochemical and packed cell volume reference intervals, we collected blood samples from 43 clinically healthy Mexican axolotls (mean body weight, 59.6 ± 17.5 g; total length, 21.1 ± 1.8 cm) under anesthesia with a 0.2% ethyl 3-aminobenzoate methanesulfonate solution. Plasma biochemical tests were performed with the use of two types of automated biochemical analyzers, and packed cell volume was measured simultaneously. Bland–Altman analysis was used to measure agreement between the analyzers. Reference intervals for packed cell volume and plasma biochemical values obtained from both analyzers were established for the Mexican axolotl. The results revealed systematic biases in values derived from both analyzers. This study has provided a baseline for the plasma biochemical profile and packed cell volume in clinically healthy Mexican axolotls. The results of this study suggest that the reference intervals for plasma biochemical values of the Mexican axolotl be customized for each analyzer.