Sildenafil citrate (SC) is a phosphodiesterase type-5 inhibitor, which acts to increase cyclic guanosine monophosphate (cGMP). This study aims to assess the effects of Sildenafil citrate (SC) on glycemic control and hematological parameters of diabetic rats induced with streptozotocin (STZ). Fifty male Wistar rats were divided into four groups (n=10/non-diabetic group; n=15/diabetic group): i. control (I), ii. SC-treated control (II), iii. diabetic (III), and iv. SC-treated diabetic (IV). Diabetes was induced by an intraperitoneal injection of STZ (50 mg/kg). SC (20 mg/kg body weight) was administered orally for six weeks. Blood specimens were taken to measure levels of serum glucose (FBG), insulin, glycated hemoglobin (HbA1c), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, prothrombin time (PT), partial thromboplastin time (aPTT), fibrinogen, protein C, and protein S. Levels of FBG, HbA1c, AST, ALT, urea, creatinine, and fibrinogen were significantly elevated in the rats with diabetes compared to the controls. Conversely, insulin, aPTT, protein C and S were significantly lower in the diabetic groups. No significant difference was seen in the PT of control and diabetic rats. No effect was found in the administration of SC on healthy control rats. Upon administration of SC to the diabetic rats, these parameters returned to normal (P<0.05). SC was found to improve glycemic control as well as microcirculatory perfusions in diabetic rats, warranting its consideration as a way to lessen diabetic complications.