Three new bridgeless single phase ac-dc power factor correction (PFC) rectifiers based on Cuk topology are proposed. The absence of an input diode bridge and the presence of only two semiconductor switches in the current flowing path during each switching cycle result in less conduction losses and an improved thermal management compared to the conventional Cuk PFC converter. The proposed topologies are designed to work in discontinuous conduction mode (DCM) to achieve almost unity power factor and low total harmonic distortion (THD) of input current. The DCM operation gives additional advantages such as: zero-current turn-on in the power switches, zero-current turn-off in the output diode, and reduces the complexity of the control circuitry. Performance comparisons between the proposed and conventional Cuk PFC rectifiers are performed based on circuit simulation. Experimental results for a 150W/48V dc at 100 Vrms line voltage to evaluate the performance of the proposed bridgeless PFC rectifier are provided.