Background: Diabetes mellitus is going to be a major cause of mortality and morbidity in near future. Control of diabetes includes changes in lifestyle and diet along with administration of antidiabetic drugs. Many antidiabetic drugs may show sideeffects or resistance for appropriate action. A suitable dietary ingredient may avoid these unwanted effects. Trigonella foenum graecum (Fenugreek) seems to be one of the most effective food ingredients having this anti-diabetic activity. Objectives: of the study were to study various important metabolic effects of Fenugreek including its antidiabetic effect in non-diabetic as well as in diabetic rats. Materials and Methods: This research included two study groups with Fenugreek administration, e.g., diabetic and non-diabetic groups; and two corresponding control groups. Serial blood glucose levels along with serum cholesterol, triglyceride, albumin and total protein levels were estimated at the end of study period. H & E, PAS stained sections and electron microscopic studies were carried out in pancreas, liver and skeletal muscles in all four study groups. Results: Study showed statistically significant control of blood glucose and cholesterol levels in both the study groups as compared to control groups. Serum albumin levels also showed significant improvement in study group. These biochemical findings were well supported by microscopic and ultrastructural findings. Conclusion: Trigonella foenum graecum (Fenugreek) reveals significant anti-diabetic effect and anticholesterol effect through its insulin-like action on insulin receptors in hepatocytes and skeletal muscles. Longer duration of study may reveal few more metabolic effects, possible side-effects and even long term effectiveness of its anti-diabetic action.