There is no doubt that loyalty is one of the most frequently explored topics. However, this might not be the case with the loyalty in the business-to-business market. That is also true about the research of the loyalty-forming constructs: it is unclear whether the constructs, which influence loyalty in B-2-C market-perceived quality, switching costs, commitment, trust, and satisfaction-have an impact on loyalty in the B-2-B market, too. The paper aims to evaluate an impact of the main drivers on the two types of loyaltybehavioural and attitudinal-in the case of B-2-B market. The survey of B-2-B service companies, performed in a small transition economy, has proved the significance of the selected factors for the measurement of loyalty. The high level of determination coefficient showed that the models included the most important factors. However, some factors had a direct impact, while other factors influenced loyalty indirectly. Switching costs and attitudinal loyalty had a direct impact on behavioural loyalty. At the same time, satisfaction had a direct impact on attitudinal loyalty, making an influence of the behavioural loyalty as well. Meanwhile, the impact of trust, perceived quality and commitment on attitudinal loyalty was strongly mediated by the perception of satisfaction.