High-efficiency stepping up operation is an important feature of the converters used in renewable power applications due to the low voltage level of photo-voltaic arrays and fuel cells. Decreasing the switching losses of the converters is an effective solution for increasing the converter efficiency, especially in high-power applications. This article presents a novel zero-voltage-transition (ZVT) interleaved dc-dc boost converter that can be used in renewable power sources to reduce switching losses. The auxiliary circuit used in the proposed converter is composed of only one auxiliary switch and a minimum number of passive components without an important increase in the cost and complexity. The main advantage of the proposed converter is that it not only provides ZVT in the boost switches but also provides soft switching in the auxiliary switch. Another advantage of the proposed topology is that the semiconductor devices used in the converter do not have any additional voltage or current stresses. Also, it has a simple structure, low cost and ease of control. In this article, a detailed steady-state analysis of the proposed converter is presented. The theoretical analysis is verified via simulation and experimental studies which are in very good agreement.