The AST/ALT ratio was estimated in 182 dogs infected with Babesia canis. Among these dogs 65 had anaemia and 68 were azotaemic. Student's t test was used to compare means of the AST/ALT ratio in anaemic and non-anaemic dogs, and in azotaemic and non-azotaemic dogs (p < 0.05). The differences in AST/ALT ratio between anaemic (1.52 +/- 1.15) and non-anaemic (1.76 +/- 1.34) dogs were statistically insignificant (p = 0.23), however, the comparison of AST/ALT ratio between azotaemic (2.68 +/- 1.52) and non-azotaemic (1.08 +/- 0.53) dogs revealed a significantly higher value of this index in azotaemic dogs (p = 0.00). The present results suggest that kidney injury contributed to increased AST activity in these dogs.