This study was aimed to assess the potential ameliorative effect of the ethanolic extract of Zingiber officinale (Z. officinale; ginger) and Nigella sativa (N. sativa; black seed) on streptozotocin (STZ)-diabetic rats.  Fifty albino rats of Wistar strain were randomly divided into five equal groups. Group 1 received saline orally (a control group). Groups 2 -5 were experimentally exposed to diabetes via intraperitoneal (i.p.) injection of STZ (55 mg/kg BW.). The 2^nd  group was left without treatment as diabetic non-treated control, while the 3^rd  to 5^th  groups were orally treated with metformin (100mg/kg BW), ethanolic extract of ginger (200mg/kg BW.) and N. sativa (300mg/kg BW.), respectively for 21 consecutive days.Blood and pancreatic tissue samples were collected at the end of the experiment for biochemical analysis. The results revealed that blood glucose, fructosamine and insulin levels were improved following treatment by metformin (99.00±4.76, 198.69±5.25 and29.82±2.35, respectively),and ethanol extract of ginger (105.20±4.87, 317.48±17.79 and13.64±0.72, respectively). Meanwhile, N. sativa extract produced insignificant decrease in glucose level (201.60±14.91) and significant improvement in serum fructosamine and insulin levels (273.20±6.39 and 21.65±1.78) if matched with the diabetic control group on the 3^rd week of the experiment. Treating of diabetic rats with metformin and N. sativa extract elicited a significant increase in blood RBCs count (6.21±0.170 and 5.63±0.135), Hb concentration (12.96±0.229 and 12.00±0.141), PCV% (46.40±1.077 and 74.72±1.085),  tissue catalase (0.32 ±0.012 and 0.25±0 .009) and superoxide dismutase activities (19.44±2.16 and 12.77±0.914), respectivelywhen compared with the diabetic group. However, administration with ginger extract produced variable changes in the erythrogram and leukogram. This study provided that Z. officinale and N. sativa extracts have significant effects on some biochemical and hematological assays, as compared with metformin known as standard antidiabetic drug. Consequently, the herbal extracts under current inquiry could have a role in alleviating the risk of some chronic complications of diabetes.