Combined oral contraceptives (COCs) have become the most common or popularly used method of reversible contraception worldwide (1). The impact of oral contraceptives (OC) on cardiovascular health remains an important issue due to the popularity of this contraceptive choice combined with the knowledge that OC usage has been linked to adverse cardiometabolic effects (2). Estrogen is believed to have cardiometabolic protection effect; but its beneficial effects have recently been queried. The aim of the present study was to determine whether or not the altered glucose tolerance and plasma lipid profile was associated with OC and due to the estrogenic or progestogenic-component in 120-180g female rats. Rats (8 per group) were divided into control, combined ethinyl estradiol-levonogestrel OC-treated (LEE) (receiving 0.75μg ethinyl estradiol/7.5μg levonorgestrel, p.o.), and low dose levonogestrel only OC-treated (LOC) (receiving 3.75 μg levonorgestrel, p.o.) groups. Rats were given distilled water (0.3ml, p.o), LEE and LOC daily for 6 weeks. Values are means± S.E.M. Glucose challenge test was performed 48- hours prior to the end of the experiment. The animals had 12-hour overnight fast and glucose tolerance was expressed as a function of the area under the tolerance curve (3,4).The results showed that treatment with a combination of levonogestrel and ethinyl estradiol led to significant decrease in glucose tolerance (370.6±14.9 vs. 280.6±10.1mmol/l) and increase in plasma triglyceride (TG) levels (105.6±9.2 vs. 63.2±1.2mg/dl) while treatment with levonogestrel only did not lead to any alteration in glucose tolerance and TG levels when compared with the control. However, treatment with a combined levonogestrel and ethinyl estradiol or levonogestrel only did not cause significant changes in total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), total cholesterol/high-density lipoprotein-cholesterol (TC/HDL-C) ratio, and fasting blood glucose. In conclusion, the present study demonstrated that the use of OC containing levonogestrel in combination with ethinyl estradiol but not levonogestrel-only OC use caused impaired of glucose tolerance associated with increased triglyceride. This indicates that estrogenic but not progestogenic component of OC may be responsible for the altered glucose tolerance and lipid metabolism in this animal model.