This paper proposes a new high voltage gain and high-efficiency dc-dc converter. The proposed topology is formed by a coupled inductor to achieve high voltage gain and low stress on the active switch. The switch voltage stress is significantly low compared to the output voltage which enables the use of a low voltage rating MOSFET. Moreover, the voltage stress on output diode is decreased to 16% of the output voltage as compared with boost and other high step-up converters. Furthermore, the utilization of coupled inductor eliminated the reverse recovery losses of diodes. The efficiency of the converter is hence improved. As compared with existing topologies, the proposed converter consists of the least number of components that decreases the overall system cost. The steady-state operation and analysis of the proposed converter are presented. The experimental results of a hardware prototype demonstrate the consistency with the theoretical analysis. The converter shows a peak efficiency of 96.7%.