Introduction: The pharmacovigilance system collects adverse events registered by physicians in their clinical practice. However, there is a low index of reports in this regard. There are various publications at international level oriented to determine causes for this low notification. In this respect, it would be valuable to count with an instrument that would diagnose the situation prevailing for México. The objective was to develop and validate a questionnaire reliable and sensible for measuring causes of low reports. Material and Methods: Experts validated the questionnaire and the final instrument was applied to 124 physician subjects that responded to the 30 final questions, and their answers were tabulated and categorized for measuring confidence and internal congruence. Alfa of Cronbach and "t" student tests were applied for the validation and test-posttest application. Results: The internal consistency value was 1.097. The different answers and scores were calculated, where the final global average in points for responses for the pilot group studied was 100.72, that translated to percentage resulted in 67% (S.D. 8). The final Cronbach alpha value obtained was 0.7. Conclusions: The validated questionnaire meets the objectives for which it was designed, and proved to be useful, reflecting the state of knowledge, abilities and attitudes.