Introduction: many studies have concluded that self-efficacy is an essential variable within the area of drug addictions and a key to maintaining abstinence and preventing relapses. The Situational Confidence Questionnaire by Annis et al. (1987), is one of the most used instruments to measure self-efficacy and has had various modifications. The Brief Situational Confidence Questionnaire (CBCS), is the shortest version with only 8 items. Objective: to obtain the factor validity and reliability of the CBCS with a clinical sample in residential modality. Method: the study was carried out with a sample of 41 volunteers patients, adolescents, and adults interned in a residential rehabilitation center. The evaluation met the standards for the development and review of instrumental studies. Results: after carrying out the exploratory factor analysis, the eight original items were left within a single factor which explains 71.39% of the variance, with a factor load between the ranges of .76 and .91, and with an internal consistency of .941. Discussion and conclusions: the Brief Situational Confidence Questionnaire presents an internal consistency with high reliability and acceptable factor loads, such as was found in other studies. Therefore, its use in Mexico is suggested as an evaluation tool in a clinical setting, with patients who are interned in a rehabilitation center. It is recommended to carry out replications with more representative and randomly selected samples. Furthermore, it is suggested to include confirmatory factor analysis to obtain greater certainty in the results.