This study sought to explore the tactical and strategic challenges, which small and medium sized service firms may face in their bid to successfully practice and implement Relationship marketing. The framework of the requirements for successful practice of relationship marketing propounded by Gronroos (1996) was used in this study to explore likely, the tactical and strategic challenges that small and medium sized service firms face in their endeavour to practice Relationship marketing (RM). A critical literature review was undertaken on the inherent characteristics of SMEs and how they pose the aforementioned challenges. Small and medium sized firms could find it strategically and tactically challenging to meet effectively, the requirements of successfully implementing and practicing Relationship marketing owing to their inherent characteristics and constraints. Researchers are recommended to empirically investigate the applicability of the ''generalized'' requirements for the successful practice of Relationship marketing in small and medium sized service firms. The study viewpoint, which is the first of its kind, demonstrates that the ''one size fit all'' approach as regards the practice of Relationship marketing does not generically apply to all business forms (large and small) hence, may not be generalized to small and medium sized service firms as well across all types of economies.