Background: Depression, anxiety, and stress are a public health issue with high prevalence in Portugal. Objectives: To determine the prevalence of depression, anxiety, and stress, as well as to analyze differences between gender, age, education level, occupational status, intake of psychotropic drugs, and perceived health status regarding levels of depression, anxiety, and stress. Methodology: A cross-sectional descriptive-correlational study was conducted with a sample of 207 users using non-probabilistic and convenience sampling. A biographical questionnaire and the Portuguese version of the Depression, Anxiety, and Stress Scale (DASS-21) were applied. Results: In this sample, 64.5% to 79.9% of users had normal to mild depression, anxiety, and stress; 6.6% to 18% of users had a moderate level; and 10.5% to 17.5% of users had a severe to extremely severe level. Depression, anxiety, and stress were more prevalent in individuals aged over 65 years, those who perceived their health as poor, and those who took psychotropic drugs. Anxiety was frequent in women. Depression was higher in individuals with a low education level. Anxiety and depression were frequent in people who were professionally inactive. Conclusion: Given the high prevalence of depression, anxiety, and stress, preventive strategies are urgent.