OBJECTIVE Subjective halitosis is a growing concern in the fields of dentistry and psychology. This study was designed to determine the association between subjective halitosis and contributing psychological factors. METHODS Data for this cross-sectional study were gathered from 4,763 participants who had answered questions on subjective halitosis and psychological factors (depression, anxiety, stress and personality traits) in the study on the epidemiology of psychological, alimentary health and nutrition (SEPAHAN). Binary logistic regression was used for data analysis. RESULTS The mean age of all subjects was 36.58 years; and the majority of subjects were female (55.8%), married (81.2%) and graduates (57.2%). The prevalence of subjective halitosis was 52.8%. The majority of subjects with the complaint of subjective halitosis were married (P<0.001) and young (P=0.07). Participants with subjective halitosis were significantly more anxious [odds ratio (OR)=1.76, 95% confidence interval (95% CI): 1.38-2.24], stressed (OR=1.41, 95% CI: 1.17-1.71) and depressed (OR=1.31, 95% CI: 1.09-1.57). Among personality traits, neuroticism was a risk factor (tertile 1 vs. tertile 2: OR=1.29, 95% CI: 1.09-1.51; and tertile 1 vs. tertile 3: OR=1.74, 95% CI: 1.43-2.13) and conscientiousness was revealed to be a protective factor (tertile 1 vs. tertile 2: OR=0.82, 95% CI: 0.70-0.98; and tertile 1 vs. tertile 3: OR=0.65, 95% CI: 0.53-0.80). CONCLUSIONS It seems that psychological factors, such as anxiety, depression and stress, as well as some personality traits, can be considered as risk factors for subjective halitosis. Multidisciplinary efforts by dental and psychological professionals must be considered to address this problem.