The aim of the paper is to understand how SMEs perceive professionalism its influences on the customer loyalty of the banks they work with. This is being explored through investigating the black box found in the relationship between these two concepts. The paper hypotheses that corporate image and relationship quality are the intervening variables in the professionalism relationship to customer loyally, while switching barriers are then serve as moderators of the relationship between corporate image and relationship quality and customer loyalty. The paper is based on a survey answered by 335 owners of SMEs in Sweden. The findings of the paper indicate that 1) increasing perception of banks’ professionalism has a positive impact on banks’ corporate image and on the relationship quality SME possesses, 2) increasing positive perception of the banks’ corporate image and increasing relationship quality leads to higher customer loyalty, 3) switching barriers do not moderate the relationship between perceived corporate image and relationship quality of the bank SME works with, 4) that perceived corporate image and relationship quality mediate the relationship between perceived professionalism of the bank in its influence on customer loyalty of SME to its bank.