During human pregnancy, fetal placental cells known as trophoblast invade into the uterine mucosal lining, coming into contact with maternal cells including a specialized population of leukocytes. In order to understand the interaction of maternal cells with trophoblast, it is useful to be able to isolate the various cell types from the fetal-maternal interface so that they may be characterized and co-cultured in vitro. This chapter details the methods we use in our laboratory for enrichment and/or purification of trophoblast cells, decidual leukocytes, decidual natural killer cells, decidual stromal cells, and decidual glandular epithelial cells from human first-trimester tissue samples.