Purpose: In the context of shared decision-making, providers need to explicitly acknowledge uncertainty with patients. However, physicians' reactions to uncertainty may influence their ability to do so. The aim of this study was to identify the socio-demographic variables which are associated with Physicians' Reactions to Uncertainty in a French-speaking sample of physicians. Methods: A cross-sectional survey was performed in a group of private practice as well as in a group of family practice teaching units in Québec, Canada. Two subscales from the Physicians' Reactions to Uncertainty (PRU) that had been translated in French were used: anxiety due to uncertainty (Cronbach =0.86) and reluctance to disclosing uncertainty to patients (Cronbach =0.79). Univariate analyses used: Pearson r correlation coefficient, Student's t test and ANOVA. Multivariate analyses used: the SAS GLM procedure. Results: 138 physicians (69 clinical teachers and 53 residents in family medicine and 16 physicians in private practice) enrolled in this study. In univariate analyses, younger age (p<0.0001), fewer hours worked per week (p=0.03), fewer patients seen per week (p=0.003), female (p<0.0001) and residency status (p<0.0001) were found to be positively associated with anxiety due to uncertainty but not with reluctance to disclosing uncertainty to patients. Having another diploma (p=0.01) was found to be negatively associated with reluctance to disclosing uncertainty to patients but not with anxiety due to uncertainty. In multivariate analyses, being a female (ß=0.483), a 1st year resident (ß=0.597) or a 2nd year resident (ß=0.972) and fewer hours worked per week (ß= - 0.012) explained 30% of the variance in the anxiety due to uncertainty score. Having another diploma (ß= - 1.996) explain 5% of the variance in the reluctance to disclosing uncertainty to patients score. Conclusions: Socio-demographic variables which are associated with anxiety due to uncertainty differed from those associated with reluctance to disclosing uncertainty to patients. In line with previous studies in this field, French-speaking female physicians experienced more anxiety due to uncertainty than their male counterparts. Number of hours worked per week and a residency status were also found to influence this type of anxiety. Having another diploma appeared to improve disclosure of uncertainty to patients. Therefore, those interested in implementing shared decision-making should tailor their interventions accordingly.