This paper proposes a two phase interleaved high step-up DC-DC converter. The interleaved structure helps to achieve reduced current ripple at the input side. The voltage gain is extended by using diode-capacitor pair and a coupled inductor with appropriate turns ratio. During turn-OFF condition, the voltage spikes appearing across the switch are reduced by using a passive lossless clamp circuit. Experimental results obtained from a 24V/240V, 200W prototype converter proves the converter's suitability for high step-up voltage conversion like photovoltaic and fuel cell applications. © 2016 IEEE.