A bidirectional relationship has been established between testosterone deficiency (TD) and type 2 diabetes mellitus (T2DM). Low testosterone level has been reported to be a predisposing factor to T2DM (Selvin et al., 2007), while recent clinical studies have shown a high prevalence of low testosterone in diabetic individuals (Dhindsa et al., 2004). However, it is not known if any relationship exists between type 1 diabetes mellitus (T1DM) and testosterone level. This study was designed to investigate the effects of TD on T1DM. Sprague-Dawley rats (male, 140-160g) were randomly divided into four groups designated as control, diabetic, orchiectomized and orchiectomized-diabetic. Diabetes was induced with alloxan (100mg/Kg BW i.m.) and orchiectomy was performed under aseptic surgical conditions. Rats were anesthetized with Ketamine (90mg/kg BW) and Xylazine (10mg/kg BW) intramuscularly, for bilateral removal of the testes. After 3 weeks, glucose tolerance was assessed by oral glucosee tolerance test (OGTT) where each rat received an oral glucose of 2g/kg BW and blood sample drawn from tail vein afterwards at intervals of 30, 60, 120 and 180 min for measurement of glucose level. The area under the glucose (AUC glucose) was calculated using the trapezoidal rule. Serum insulin was analysed using ELISA system and lipid parameters were analysed enzymatically with kit obtained from Randox, UK. Oxidative analyses of the liver homogenate were carried out using previously described standard methods (Morakinyo et al., 2011). Values are means ± S.E.M., compared by ANOVA. The results shows that baseline glucose values in the orchiectomized-diabetic group was lower (217.5±18.81mg/dl P<0.05) compared to diabetic group (340.75±17.15), although this was higher than the baseline glucose for both control (99.67±3.23) and orchiectomized group (95.5±4.60). The AUC during OGTT showed that the orchiectomized-diabetic group expressed an enhanced ability to metabolize glucose than the diabetic group. (51139.65±1592.52 vs. 77961.00±2806.43, P<0.05 respectively). The MDA level in the diabetic group was increased (103.20±5.05, P<0.05) compared with control and orchiectomized group (87.12±4.18, 78.08±3.78 µmol/ml respectively). More so, there was a decrease in GSH activity and an increase in SOD activity in the diabetic group compared with control. (GSH: 1.09±0.13 vs. 1.77±0.15, SOD: 2.68 ±0.11 vs. 2.03 ± 0.20, µmol/ml P<0.05). Meanwhile, the activities of GSH and CAT were significantly reduced in the orchiectomized as well as orchiectomized-diabetic group (GSH: 0.17±0.03, 0.16±0.03, CAT: 5.39±0.22, 3.75±0.28, P<0.05, respectively) when compared with both control and diabetic group (GSH: 1.77±0.15, 1.10±0.12, CAT: 10.85±0.99, 10.95±0.77 respectively). These data indicates that testosterone promotes glucose intolerance and oxidative stress under type 1 diabetic condition.