Purpose - The purpose of this paper is to study the theoretical foundation of the relationship quality concept and loyalty, and to study the relationship between relationship quality, its antecedents and loyalty. Design/methodology/approach - An empirical study was conducted in the parapharmaceutical sector. Data collection was carried out through the direct administration of a questionnaire to a sample of 300 pharmacists dealing with sales representatives of the parapharmaceutical products. Findings - The results show that there is a significant relation between the antecedents of relationship quality, namely, interpersonal communication, relational contact, conflict resolution and client-oriented behavior, and relationship quality itself. Relationship quality has also an impact on loyalty which is accounted for positively by satisfaction, and negatively by affective conflict. Research limitations/implications - The authors limited the scope of the study to purifying measurement scales and testing the links between the various concepts. Practical implications - The paper sheds light on the action leverages that suppliers have to work on so as to improve the quality of their relation with their clients. Originality/value - Compared to most previous research works which did not go beyond the probing of antecedents of relationship quality separately, the most important contribution of the study lies in taking into account some important antecedents in the study of the influence of antecedents of relationship quality on each dimension of relationship quality.