Vitamin B12 is an essential water-soluble vitamin, commonly found in a variety of foods. The present study investigated the effect of Vitamin B12 on tramadol-induced hepatorenal dysfunctionand DNA fragmentation in rats. Thirty-two (32) adult male Sprague–Dawley rats were randomized into four groups of eight (n=8) rats each. Group A served as control and was given 1 ml normal saline, group B received 50 mg /kg body weight (bwt) of tramadol (TRM), group C received 0.5 mg/kg bwt of vitamin B12 (VB12) and group D received 50 mg /kg bwt TRM and 0.5 mg/kg bwt of VB12 through gastric gavage daily for 8 weeks. The biomarkers of hepatorenal damage, antioxidant enzyme activities, myeloperoxidase (MPO), nitric oxide (NO), inducible nitric oxide synthase (iNOS), reactive oxygen and nitrogen (RONS) species and lipid peroxidation (LPO), lipid profile, tumour necrosis factor-alpha (TNF-α), nuclear factor-kappa B (NF-ĸB), interleukin-1 β (IL-1β) interleukin-6 (IL-6) and caspase-3 activity, cardiovascular risk indices, total ATPase, protein thiols, DNA fragmentation and liver and kidney histology were assessed.The increase in biomarkers of hepatorenal toxicity by TRM was alleviated by VB12. Also, the decrease in antioxidant status as well as the elevation in RONS and LPO were assuaged in rats cotreated with TRM and VB12. In addition, TRM-mediated increases in TNF-α, IL-1β, IL-6, NF-kB and caspase-3 activity were significantly diminished in the liver and kidney by VB12. Hepatorenal histopathological lesions were alleviated by VB12.Vitamin B12 therefore, assuaged TRM-induced oxidative stress, inflammation and caspase-3 activation in the liver and kidney.