Second cancer in a women with a primary gynecological malignancy could reflect a common etiology or sequealae of a potentially carcinogenic treatment. The aim of the present study was to determine the incidence rate of second primary cancer in a cohort of women with primary gynecological cancer and patient characteristics, namely age, diagnosis, type of treatment, and duration of follow-up. The study cohort comprised 925 Israeli Jewish women with histologically confirmed gynecologic malignancies. The file was linked by computer matching to the Israel Cancer Registry for identification of second primary cancers. Standardized incidence rates (SIRs) for site-specific as well as for all cancer were computed. A significant excess for subsequent leukemia among ovarian (SIR 10; 95% CI 1.1-36.1) and uterine corporal cancer patients (SIR 10.0; 95% CI 2.7-25.6) was found. The significant increase in leukemia was treatment-related and limited to patients treated with radiotherapy. Age older than 60 years constituted a significantly unfavorable factor. The estimated probability of developing a subsequent cancer at 175 months is 6.1%. Physicians should be aware of the possibility of a second primary malignancy when prescribing treatment and during follow-up.