Primordial germ cells (PGCs) from embryos of the giant freshwater prawn,Macrobrachium rosenbergii, are remarkably large with granulated cytoplasm. The prominent nucleus contains several conspicuous nucleoli. The 5.5–6.5-day-old embryos are good sources for PGC isolation since they contain a relatively high proportion of the PGCs and the embryonic cells at these stages are easily dissociated. Embryos 5.5–6.5 days old and 14.5–16.5 days old were homogenized, and the cell suspensions were either mechanically or enzymatically dissociated. The dissociated cell suspensions were fractionated in the three-layered Percoll discontinuous gradient. An average of 38.8±5.8% and 27.5±4.4% PGCs were obtained at the interface between 25% and 30% and between 30% and 35% Percoll, respectively, following mechanical dissociation of cells of 5.5–6.5-day-old embryos.