Contradictory opinions about some stages in a new service development cause many uncertainties, especially when transferring actions of theoretical implementation into practice. Such ambiguities are particularly typical for the process of conception formation, also evaluation and service system creation. The aim of the paper is to provide a justified model of new service concept(s) formation, its assessment and service system (new service technology) designing. Because of the lack of data about service concept formation, reference was also made to the sources of information about product concept creation. Scientific information on the issues of concept formation was analysed (systematised, structured and synthesised basing on sparse works of other authors) after being assessed in terms of logic and integrity, availability and practical appropriateness for service business. Research findings are used to develop a process model. It consists of the following main components: determining the purposefulness of new service development, concepts designing, concepts assessment according to two different sets of criteria, decision making about service system designing (new service technology designing). Application of the proposed model will show a real ways for the formation of new service concepts. Flexible construction of the model allows reducing time needed for the evaluation and implementation a new service.