Background and need of the study: Effects of yoga is studied by many scholars; however, little attention has been given to the phenomenon of premenopausal female participants. So there is need to observe effect of yoga on mental health and flexibility in premenopausal women. Methodology: Observational study, convenience sampling was done, participants who belong to age group between 40-50 were included in the study. Oral consent was obtained from every participant. Participants were divided into 2 group, group A: who are practising yoga since last 3 years and group B: who were not practicing yoga. Outcome measures 1) V sit and reach test for flexibility and 2) DASS scale to assess depression, stress and anxiety used. Result: Mean DASS score was(6.45+3.85) and (13.20+5.36) for group A and group B respectively and mean score for flexibility was (20.60+5.36) and(13.35+5.25) for group A and group B respectively. For comparison of outcome measures, Mann-whitney U test was applied, test result shows that, there is significant difference between groups in flexibility (U=37.5, p=0.0001) and DASS score (U=50.5, p=0.0001). Conclusion and clinical application: Yoga has shown good control on mental health and flexibility in premenopausal females practicing yoga. So, We can encourage premenopausal female to practise yoga regularly. Keywords: Premenopausal, Yoga, Depression, Anxiety, Flexibility.