The synthesis of poly(trifluoropropylmethyl)siloxane (PTFPMS) by anionic ring-opening polymerization of 1,3,5-tris(trifluoropropylmethyl)cyclotrisiloxane (F-3) was studied in miniemulsion using didodecyldimethylammonium bromide (DDDBr) as emulsifier and sodium hydroxide as initiator. This new process of polymerization produced well-defined alpha,omega -dihydroxylated polymer in very high yields and with molar masses ranging from 2000 to 30 000 g mol(-1). A kinetic study showed that polymerization occurs in two stages. During the first stage, which corresponds to the anionic kinetically controlled ring-opening polymerization of F-3, the maximum nonequilibrium yield is close to 100%. The second stage involves condensation and backbiting reactions. The delay between these steps offers a broad "termination window" for achieving high polymer yield.