Women with mental illness (WMI) are more likely to experience unreported sexual and reproductive health (SRH) problems. Mixed-method research studies with the strengths of quantitative and qualitative approaches provide deeper insight into SRH issues of WMI. A sequential explanatory mixed-method design was used to understand better the SRH problems of WMI attending tertiary care psychiatry hospital. In phase 1, a survey was conducted to identify if they have SRH problems. Women who were identified to have SRH problems were part of Phase II. In this phase, in-depth interview was conducted to explore their lived-in experiences. Integration at the method level was adopted by connection through sampling. Using a narrative approach, integration was accomplished at the level of interpretation and reporting. Among the users, 261 (64.6%) female sterilization, 244 (93%) was the most common, and the other methods like coitus interruptus, male condoms, and intrauterine devices were reported less. Of the non-users, 137 (33.9%) WMI 100 (73%) were unaware of the best family planning approach. Most of them, 377 (93.3%), were ignorant about sexually transmitted infection (STI) symptoms. WMI reported 62 (15.3%) unusual foul-smelling vaginal discharge and 58 (14.4%) genital ulcers, with poor treatment-seeking behavior. Sexual dysfunction in desire, arousal, lubrication, orgasm, satisfaction, and pain were also reported. The findings were described in a single report based on the quantitative data followed by themes obtained from qualitative interviews using weaving techniques under the headings of contraceptive use and its awareness, prevalence of STI symptoms and its treatment, and sexual health experiences. Data integration demonstrated that one-fourth of WMI had inadequate awareness of contraceptive use, were ignorant of STI symptoms, and experienced sexual dysfunction.