Requirements prioritization is recognized as a critical but often neglected activity during software development process. To achieve a high quality software system, both functional and non-functional requirements must be taken into consideration during the prioritization process. Although in recent past years a lot of research has been devoted to requirements prioritization problems, research on proposing approaches to consider both functional and non-functional requirements throughout the prioritization process is still limited. In this article, we propose an approach using Hybrid Assessment Method (HAM) to prioritize both functional and non-functional requirements simultaneously. The effectiveness of the proposed approach has been evaluated through an experiment with the aim of comparing the approach with the other state-of-the-art-based approach, Analytic Hierarchy Process (AHP).