Objective : This study evaluated the role of smartphone application in the self-assessment of three psychiatric symptoms: stress, depression, and suicidal ideation. Methods : A total of 5,646 respondents were evaluated with three scales (Perceived Stress Scale, PSS, Center for Epidemiologic Study for Depression, CES-D, Scale for Suicidal Ideation, SSI) via smartphone application 'mindscan'. We analyzed the sociodemographic variables, the levels of three symptoms, and the association between the scores on all three scales. Results : The mean total scores of PSS, CES-D, and SSI were 24.86, 35.15, and 18.03, respectively. Women showed significantly higher scores on PSS, CES-D, and SSI when compared with men. Younger users showed a significantly higher score on all three scales when compared with older users. The scores on all three scales were higher than in other studies with off-line surveys. The PSS was positively correlated with CES-D (r=0.690), and with SSI (r=0.367). The CES-D was positively correlated with SSI (r=0.540). Conclusions : A smartphone application for mental health based on three scales (PSS, CES-D, and SSI) is a relatively useful screening tool compared with off-line general population surveys. The association between the three scales reflects the relationship between the three psychiatric symptoms observed in clinical practice.