Parasitic infection during pregnancy is common. With most parasites, primary prevention is very effective in avoiding infestation. With the exceptions of malaria, toxoplasmosis, and African trypanosomiasis, when infection does occur, treatment decisions should be based on the impact of the infection on the patient and her fetus on an individual basis. When treatment is indicated, selection of medications with the least potential to harm the mother and more particularly the developing fetus is essential.