Many diabetic patients develop serious complications during the course of the disease, including cardiovascalar disorders, nepropathy, neuropathy and retinopathy. Because some physiological changes occurring in diabetes mellitus patients could alter the pharmacokinetics of drugs used to treat the disease, the pharmacokinetics of gentamycin was investigated after intravenous administration (2 mg/kg) to control rabbits and acute or chronic alloxan-induced diabetes mellitus rabbits (AIDRs). After intravenous administration, the serum concentrations of gentamycin were significantly higher between 6 and 12 hr in chronic AIDRs compared with those in control rabbits. The AUC was significant greater in chronic ($31.91;{pm};3.76;{mu}g/ml{cdot}hr$) AIDRs than that in control ($21.60;{pm};2.45;{mu}g/ml{cdot}hr$) rabbits. Total body clearance (CLt) in AIDRs were significantly decreased compared with that in control rabbits. Cumulative urinary excretion of gentamycin was decreased, although not significantly, in AIDRs compared with that in control rabbits.