Background and Objective: The present survey was a preliminary to a European research project on the attitude and knowledge of healthcare professionals towards the use of medical cannabis. The objective was to evaluate the readability, understandability, and relevance of a first version of the study questionnaire before preparing the finalized questionnaire, which will be subsequently proposed to European healthcare professionals on a large scale. Methods: A cross-sectional study was conducted between December 2019 and May 2020. We established an electronic evaluation questionnaire relating to the study questionnaire. This evaluation questionnaire was proposed to multidisciplinary experts from all over Europe. Feedback from the evaluation questionnaire was considered for improving and finalizing the study questionnaire. Results: 66 evaluation questionnaires were collected from nine European countries (Cyprus, France, Germany, Italy, Lithuania, Portugal, Spain, Sweden, United Kingdom), which corresponded to a participation rate of 41.5%. Most participants were women (65.2%, n = 43). The mean age was 39.5 years ± 11.6. Each participant could specify several occupations. There were 25 pharmacologists, 24 physicians, ten pharmacists, four university teachers, three epidemiologists or public health experts, one nurse, one biotechnologist, one microbiologist, and one police researcher. Overall, 84.8% of participants were interested in the topic of the survey on the knowledge and attitudes of healthcare professionals towards recreational and medical cannabis across Europe. Participants were satisfied with all but six of the proposed questions. In addition, two additional questions were subject for comments despite a high level of satisfaction. Consequently, the concerned questions (n = 8) were modified. Conclusion: This evaluation survey was a necessary step to improve the quality of the future research project. The positive feedback encourages the authors to proceed with the project on a European scale, scheduled for 2021.