The interest for high gain DC-DC converter has grown recently align with renewable energy resources deployment. In particular, the interests are in high gain converters without installing additional power switches and/or other passive components in the circuit. Thus, this paper presents a non-isolated single switch converter with ultra-high voltage gain (UHG) suitable for most of renewable energy resources conversion system such as photovoltaic applications. The suggested converter achieves high voltage gain and around to 93% efficiency, with just a single MOSFET operating within reasonable duty cycle range. Furthermore, in this UHG converter, the MOSFET is turned on in zero current switching (ZCS) condition and the diode recovery problem is resolved. The operating mode of the suggested UHG converter, steady-state mathematical analysis, circuit parameters such as voltage stress on semiconductor switches and converter gain are discussed in detail. Comparisons have been made with similar topologies available in the literature and finally, in order to confirm the operation of the suggested UHG topology, experimental results based on 200W (20V input, 320V output voltage) are reported.