Objective: To evaluate the serum triglyceride and lipoprotein-cholesterol levels in subjects with and without luteal phase defect. Method: Early follicular and midluteal phase serum triglycerides, lipoprotein-cholesterol and progesterone levels were assessed in 19 subjects with and in 73 subjects without luteal phase defect. The criterion for diagnosis of luteal phase defect was histological development of endometrium delayed for more than 2 days according to the chronological day. The data were analyzed by paired and unpaired t tests, Chi-square test and correlation analysis. Results: The early follicular serum triglyceride and lipoprotein-cholesterol levels of the two groups were similar (p>0.05). The midluteal serum progesterone levels of the subjects without luteal phase defect was significantly higher than those of the patients with luteal phase defect (p<0.01), and the midluteal triglyceride and lipoprotein-cholesterol levels of the two groups were also similar (p>0.05). The midluteal serum progesterone levels had no significant correlation with the serum triglyceride or lipoprotein-cholesterol levels (p>0.05). Conclusion: Serum triglyceride or lipoprotein-cholesterol levels, which were similar in subjects with and without luteal phase defect, does not play a significant role in the ethiopathogenesis of this disease.