Abstract Background Health literacy (HL) has become a subject of major interest in public health worldwide. It is known to be linked to self-efficacy in care use and to global health status, and a non-negligible frequency of problematic or inadequate levels of HL in populations worldwide is reported. As this has yet to be evaluated in France, the present study aimed to evaluate the HL level of patients in a French emergency department (ED). Methods We conducted a descriptive, cross-sectional observational, single center study in the ED of the Lyon Sud hospital (Hospices civils de Lyon, Lyon, France). The primary endpoint was the HL level of the patients determined according to the score obtained using the 16-item European Health Literacy Survey Questionnaire. The secondary endpoint was the identification of sociodemographic factors associated with the HL level. Results A total of 189 patients were included for analysis. 10% (95% CI [3%; 17%]) of the patients had an inadequate HL, 38% (95% CI [31%; 45%]) had a problematic HL, and 53% (95% CI [46%; 61%] had an adequate HL. In multivariate analysis, age and perceived health status were independent predictors of the HL level; OR =0.82 (95% CI [0.69; 0.97]; p =0.026) for a 10-year increase in age, and OR =1.84 (95% CI [1.22; 2.82]; p =0.004]). Conclusions The HL level of the patients in the ED studied herein was similar to that found in the population of France and other European countries and was influenced by age and perceived health status, which are both associated with care needs. It may be therefore interesting to explore in future studies how taking into consideration HL in the general population may lead to a better self-efficacy in care and optimize the use of the healthcare system.