OBJECTIVES: To know the frequency and causes of low value surgical practices, according to the opinion of surgeons and anesthetists, and to determine their degree of knowledge about the Spanish "Choosing wisely" initiative. METHODS: Cross-sectional observational study, based on a self-administered online questionnaire through an opportunistic sample of 370 surgeons and anesthetists from three Spanish regions, contacted through Scientific Societies. The survey took part between July and December 2017. RESULTS: A patient profile requesting unnecessary practices was identified (female, 51-65 years old and unaffiliated disease). The frequency of requests was weekly or daily for 50.0% of the professionals, of whom 15.1% acknowledged succumbing to these pressures. To dissuade the patient, clinical reasons (47%) were considered the most effective. To increase control and safety in the case was the main reason to indicate them. The greatest responsibility for overuse was attributed to physicians, defensive medicine and mass media. Assessing professionals' knowledge on unnecessary practices, an average of 5 correct answers out of 7 was obtained. Some 64.1% of the respondents were unaware of the Spanish "Choosing wisely" initiative. CONCLUSIONS: Low value surgical practices are perceived as a frequent problem, which requires an approach entailing intervention with patients and the media as well as profession