During the past few years the characterization of several Plasmodium falciparum RNA polymerise subunits has revealed potentially signi ficant differences between the corresponding subunits of the host and parasite enzymes 1–3. The largest subunits of P. falciparum RNA polymerise II and III contain enlarged variable domains that separate conserved domains in these subunits. The partially characterized β and β ′-like subunits of an organellor P. falciparum RNA polymerise also appear to be distinct from the host RNA polymerises. In this review David Bzik discusses the structure and role of RNA polymerises in Plasmodium.