Pulse Field Gel Electrophoresis (PFGE), unlike conventional electrophoresis, can resolve DNA fragments greater than 30 kb and is a highly discriminatory molecular typing method. Here we describe a PFGE protocol for bifidobacteria characterized by a short lysis time determined by the addition of lysis reagents to the initial cell suspension, a reduced incubation period of the plugs in proteinase K, and an improved washing plug step with preheating of the buffer in a shaking incubator.