This report describes the pharmacokinetic profiles of chronically administered oral isoniazid and rifampin in one adult male and one adult female Asian elephant (Elephas maximus) that were asymptomatically infected with Mycobacterium tuberculosis. Rifampin's half-life was reduced when compared to previous single-dose pharmacokinetic profiles of healthy uninfected Asian elephants. Both elephants experienced delayed absorption of isoniazid and rifampin as compared to previous pharmacokinetic studies in this species. The altered pharmacokinetics of both drugs in repeated-dosing clinical situations underscores the need for individual therapeutic drug monitoring for tuberculosis treatment.