Hematologic neoplasms diagnosed during pregnancy, present significant difficulties in patient management. Besides the strictly medical facts, moral, ethical and religious issues should be strongly considered. For the optimal management of individual situations an integrated multidisciplinary approach is mandatory. Hodgkin's disease, acute leukemias, non Hodgkin's lymphoma and less frequently chronic myelogenous leukemia have been reported in pregnant women. Curative treatment for most of these diseases include intensive chemotherapy regimens. Potential damage to the fetus is a major concern, due to the teratogenic effects of antimetabolites, alkylating agents and radiation therapy. Effect of pregnancy in each of these neoplasms is discussed. Although some rules of management exist, dangerous generalizations should be avoided. Particular obstetric considerations such as timing of delivery, and therapeutic abortion should be carried out on an individual basis. The emotional impact of the situation must not be underestimated.