Background Communication of bad news plays a critical role in the physician-patient relationship, and a variety of consensus guidelines have been developed to this purpose, including the SPIKES protocol. However, little is known about physicians’ attitudes towards breaking bad news and to be trained to deliver it. This study aimed to develop and validate a self-report questionnaire to assess physicians’ attitudes towards principles of the SPIKES protocol and training on them. Methods The Breaking Bad News Attitudes Scale (BBNAS) was administered to 484 pediatricians and 79 medical students, recruited at two scientific conferences and two medical schools in Brazil. The questionnaire structural validity, reliability, and associations with other variables were tested. Results The BBNAS showed adequate validity and good reliability, with two factors measuring attitudes towards the SPIKES strategy for braking bad news (α = 0.81) and the possibility to be trained on it (α = 0.77), respectively. Conclusion The novel questionnaire is a psychometrically sound measure that provides information on physicians’ agreement with the SPIKES protocol. The BBNAS can provide useful information for planning training and continuing education programs for clinicians on communication of bad news using the SPIKES as a framework.