In Pakistan HIV prevalence among PWID is estimated at 38%, more than double global and regional prevalence estimates. Although the majority of the 160,000 people living with HIV in Pakistan are men, in 2018, more than one quarter (27%) of new HIV infections occurred among women. The findings of this research indicate that PWID living with HIV in Pakistan continue to face barriers to ART adherence with just over half (55%) of our sample of 5,482 MWID assessed as adherent. Among 4,121 female spouses of HIV positive MWID who had a minimum of one HIV test result: 243 HIV infections were observed at first test (5.9% baseline HIV prevalence), 109 incident HIV infections were observed for a HIV incidence rate of 1.5 per 100 person years. The overall HIV prevalence was 8.5%. More needs to be done to support early intervention to prevent HIV transmission to female partners of HIV positive MWID, including provision of HIV pre-exposure prophylaxis (PrEP) to female spouses at high risk of HIV transmission, particularly young women and women whose husbands are not receiving, or have difficulty adhering to ART.