The purpose of the paper is to explore the structure of New Services Development (NSD) process in Knowledge Intensive Business Service (KIBS) companies. In particular, it aims at investigating to what extent the NSD process is formalized and what factors influence the level of formalization in different KIBS sectors. Considering the exploratory nature of the research, the complexity and novelty of the topic as well as the intention to analyse it at a practical level the case study method was adopted. Four companies of different KIBS sectors were investigated which helped to analyse the NSD process in totally different environments characterized by different knowledge bases. The research was international and included companies from Italy and Russia. The main contribution of the paper is that it addresses a topic (i.e. the NSD process in KIBS companies) that has been scarcely investigated in the literature, even if it is especially crucial. In particular, due to the selection of a sample of cases, the study allowed to investigate companies performing different activities and possessing different kind of knowledge. This analysis puts in evidence that the level of formalization of the NSD process is influenced by the activity of the company, its strategic position on the market, and the nature of its knowledge base. The paper can be the initial step to identify and classify the variety of schemes used by KIBS companies for the NSD process. Furthermore, the study reveals the key factors that can affect the level of formalisation of the NSD process, and provides suggestions on which approach can be more adapt to introduce new services in a more effective way in different situations.