Aim: substantiation of methodical approaches to assessing the effectiveness of marketing developments to determine the quality of service to pharmacy visitors, the formation and evaluation of their loyalty and conducting research on the effectiveness of the implementation of these developments in the activities of pharmacies. Materials and methods: pharmacy reporting, logical, comparative analysis, grouping, content analysis, economic and statistical methods. Results. Methodical approaches to the evaluation of the effectiveness of marketing developments to determine the quality of service to pharmacy visitors, the formation and evaluation of their loyalty are substantiated. It is proposed to determine the results of marketing measures of social and psychological orientation taking into account the time lag (one year after implementation), and the interpretation of indicators through the prism of the relevant results of the control pharmacy, where no marketing developments were implemented (to eliminate seasonal fluctuations and other external factors). The average value of a check per year, the number of checks per year and the average value of a check in the month of the beginning of the implementation of these developments were chosen as indicators for assessing the effectiveness of marketing developments. It is shown that in pharmacies where marketing developments were implemented, the improvement of the researched indicators grew at a faster rate compared to the control pharmacy. Conclusions. Researches have shown the presence of socio-economic effect in pharmacies in the implementation of marketing developments to determine the quality of service to pharmacy visitors, the formation and evaluation of their loyalty. Key words: efficiency of marketing developments; measures of social and psychological orientation; time lag; control pharmacy; socio-economic effect.