BackgroundThe Depression Anxiety and Stress Scale (DASS) is a promising tool compared with traditional measures because of its greater divergent validity. Unlike the original DASS-42, the DASS-21 version still lacks validation studies particularly in Asian populations.AimTo validate the psychometric properties of DASS-21 among nursing and midwifery students.Subjects and methodsData were collected at three time points, the beginning, middle and end of the semester, from students enrolling in the positive thinking module. Reliability statistics, floor and ceiling effects, and factor analysis were computed.ResultsOne hundred twenty-six data points were used where participants reported mild stress levels (mean=14.84.18), moderate anxiety levels (mean=13.3 +/- 3.45) and mild depression levels (mean=12.3 +/- 3.40). DASS-21 showed excellent internal consistency reliability estimates except for item 2. Discriminant validity was an issue, and it was observed that 9 items, instead of 21, provided the best model fit ((2)=57.1, p<0.001, CMIN/DF=2.380, SRMR=0.037 and GFI=0.904).Conclusion The final model was suggestive of a quadripartite model. Further validation is needed for DASS-21, taking into account these issues and re-testing the instrument to determine whether it is psychometrically sound and valid for use in Asian populations.