Cancer is the second leading cause of death during the reproductive years complicating between 0.02% and 0.1% of pregnancies. The incidence is expected to rise with the increase in age of childbearing. The most common types of pregnancy-associated cancers are: cervical cancer, breast cancer, malignant melanoma, Hodgkin's lymphoma, nonHodgkin's lymphoma and ovarian cancer. The relatively rare occurrence of pregnancy-associated cancer precludes conducting large, prospective studies to examine diagnostic, management and outcome issues. The treatment of pregnancy-associated cancer is complex since it may be associated with adverse fatal effects. In pregnant patients diagnosed with cancer during the first trimester, treatment with multidrug anti-cancer chemotherapy is associated with an increased risk of congenital malformations, spontaneous abortions or fetal death, and therefore, should follow a strong recommendation for pregnancy termination. Second and third trimester exposure is not associated with teratogenic effect but increases the risk of intrauterine growth retardation and low birth weight. There are no sufficient data regarding the teratogenicity of most cytotoxic drugs. Almost all chemotherapeutic agents were found to be teratogenic in animals and for some drugs only experimental data exist. Moreover, no pharmacokinetic studies have been conducted in pregnant women receiving chemotherapy in order to understand whether pregnant women should be treated with different doses of chemotherapy. This article reviews the available data regarding the different aspects of the treatment of cancer during pregnancy.Cancer is the second most common cause of death during reproductive years (1). It complicates approximately 0,02 -0,1% of all pregnancies (2). However, the current trend to delay pregnancy and the age-dependent increase in the incidence of several malignancies (3) are expected to raise the occurrence of pregnancy-associated cancer.The incidence of specific malignancies in pregnant women is similar to that of non-pregnant women of reproductive age (4). The most frequent malignancies associated with pregnancy are cervical and breast cancer, malignant melanoma and Hodgkin's lymphoma. Less frequent malignant tumors are leukemia, ovarian and colorectal cancer (5).When cancer occurs during gestation, it poses a very difficult challenge to the pregnant patient, her relatives and the medical staff. The benefit of the diagnostic work-up and the use of antiblastic chemotherapy (AC), radiotherapy (RT) and surgery should be weighed carefully against their risk to the unborn child. This often raises conflicts between optimal maternal therapy and fetal well-being. Generally, systemic therapy for cancer in pregnancy must be individualized and may be different if the patient is diagnosed during the first versus the second or third trimesters. AC during the first trimester may cause more severe fetal effects, and when malignancies requiring AC are diagnosed during the first trimester, termination of