Background: More than 500 million people worldwide are obese and around 320 million adults have type II diabetes, thus these two diseases are accounted as the fundamental health care problems. There is such a strong association between obesity and diabetes that the term diabesity is proposed for this connection. Since anti-obesity drugs have many side effects, experts have very few tools to fight obesity, while high doses of carnitine has no side effects compared to other drugs. Objectives: The current study aimed to evaluate the effect of L-carnitine supplementation with low-calorie diet on the metabolic status in obese women with type II diabetes. Patients and Methods: In this study, 60 obese premenopausal women with type II diabetes were randomly selected from the patients who referred to the Diabetes Clinic of Tabriz Red Crescent; they were 20 - 50 years old with a BMI greater than 30. The subjects were divided into two groups, case and control. Following the measurement of weight, waist circumference and recording personal information, weekly food intake program (based on a low calorie diet) was given to patients. For about 8 weeks, the case group received L-carnitine supplement (2 grams daily) combined with the low calorie diet, and the control group received placebo plus low-calorie diet. In this study, low calorie diet was defined as a regimen of 500 kcal lower than the patients required energy. Blood samples (5 mL of venous blood) were taken from all patients in the sitting position, and in fasting condition (for about 10 - 12 hours) between 7:00 AM and 9:00 AM. After separation of plasma by centrifugation for ten minutes in 3000 g, samples were analyzed to measure fasting blood glucose, lipid profile and insulin resistance. Results: The results showed that L-carnitine supplement with low calorie diet reduced fasting blood glucose, triglycerides, cholesterol and LDL-C (Cholesterol, LDL-cholesterol) levels and decreased insulin resistance