This paper aimed to develop scales to measure the adoption of the e-CRM systems in service firms. A qualitative study consists of 10 semi-structured interviews to explore the intention of marketers to adopt the e-CRM system; we opted for an inductive approach for the generationof items, since the scales in the literature are not adapted to the context of this study. We chose six expertsto take part in the survey; data collection was carried out through interviews; these experts judged the relevance of each of the 27 items generated. During the 6 interviews, we noted several relevant impressions and remarks from the experts. Once the content validity for the development of the measuring instrument has been designed, a test-pilot will be carried out. The objective of the test pilot is to verify the reliability of the items. Three hundred forty managers from different service firms have been selected to participate in this test. Factorial analyzes are considered necessary to identify the main factors explaining the results obtained. The results of the exploratory factor analysis generated three factors. We choose the smart PLS approach to conduct a confirmatory factor analysis to verify the reliability and validity of the scales. A reliable and valid scale was developed to measure the two dimensions of adoption of the eCRM system: the testability and the observability of the e-CRM system. Since this study was 2 conducted in Tunisia, the generalizability of the CRM scale has to be tested in other countries. In addition, cross-sectional data were used in this study. Future studies should have applied to identify the relationship between CRM and business performance. The findings validate the observability and, the testability encourage the adoption of e -CRM system