OBJECTIVE Endometrial biopsy has been an important way of assessing infertile couples for several years. In this review of a wide-ranging series of endometrial biopsies of infertile couples in the Turkish population it was our aim to find the distribution of results according to the years 1956-1966, 1967-1980, 1981-1992. METHODS University hospital. METHODS 12,949 endometrial biopsies, referred to our gynecological pathology laboratory for infertility investigation between 1956 and 1992. METHODS Patient report files from pathology laboratory data, analyzed retrospectively. The assessment of the biopsies is made by the same pathologist. RESULTS 78.8% of cases had primary infertility, 21.2% secondary. Most of them were in the age group 26-35 years (48.8%). 37.58% of cases were found to show normal secretory endometrium, 20.95% proliferative endometrial changes, and 28.22% signs of luteal phase defect (LPD). Other local endometrial factors were also encountered, but in 1.79% the sample was considered insufficient for diagnosis. Moreover, in nine cases, malignancy was diagnosed with the help of endometrial biopsy. During the study period, cases of normal secretory endometrium and tuberculous endometritis were observed to decrease and LPD to increase significantly. It is worthy to note that in only 28 (0.21%) cases had endometrial biopsies been performed during a pregnancy cycle. CONCLUSIONS We conclude that endometrial biopsy not only shows the hormonal response of endometrium but gives additional information about the local factors of endometrium concerning atrophy, specific and non-specific infections, and malignancy.