SummaryThe detection of enzymatic deficiency in cultured amniotic cells from second trimester pregnancies is presently used for prenatal diagnosis of lysosomal diseases. The possibility of obtaining and processing trophoblast tissue at 8‐10 weeks of gestation would permit first trimester prenatal diagnosis. Using trophoblast tissue samples from normal fetuses before voluntary abortion and from placenta after therapeutic abortions of fetuses affected by several lysosomal diseases, we conclude that early diagnosis of lysosomal disorders would be possible.