Despite effectiveness in research, the efficacy of screening and brief intervention (SBI) for risky substance users is not adequately understood in routine clinical practice. Primary healthcare professionals (n = 103) from three cities in a metropolitan area in Brazil were trained and supervised in SBI and then screened 40 patients. One year later, meetings were held in each city to obtain feedback. Twenty professionals who fulfilled the task (Yes [Y]) and 24 who did not (No [N]) were individually interviewed about their SBI experience. Reports were independently interpreted and codified by two researchers. The Y and N groups reported the same barriers and positive beliefs, but only the Y group reported no negative issues. The present study lasted from 2007 to 2009.