Monoclonal antibodies (mAbs) are the cornerstone of the treatment of several types of tumors, but their use in pregnant women is not clearly defined. Here, we report and analyze all available data on mAb treatment in pregnant cancer patients. A literature search was performed from 2000 until January 2013 and all articles addressing safety of mAbs during pregnancy were reviewed. We found very few data on the use of bevacizumab in pregnant women. However, owing to its antiangiogenic effects and possible consequences on fetal development, it should be avoided during pregnancy. Trastuzumab administration has been associated with an elevated incidence of oligohydramnios and poor neonatal outcomes, particularly when prescribed after the first trimester for repeated infusions, and therefore it is not recommended. Rituximab does not seem to be teratogenic, but a transient prolonged neutropenia in the newborns was reported, without major infectious consequences in most cases. Few data are available about other mAbs, and hence their use during pregnancy remains discouraged.