Background: As a systemic immune-mediated illness, psoriasis must be detected and diagnosed in vulnerable individuals early in order to reduce disease burden and enable early treatment of the disease's symptoms. Due to the rising frequency of despair, anxiety, and suicidal thoughts among psoriasis patients, the effect of psoriasis on psychological and mental health is presently a crucial issue. Objective: The aim of the current study was to evaluate impact of psoriasis on female sexual function and to study changes that might occur in response to treatment in moderate and severe psoriasis. Patients and methods: In this case-control study, there were 90 female psoriatic patients and 90 matched controls. The patients underwent thorough history-taking as well as thorough dermatological examination. Using the PASI score, the illness severity was evaluated. The female sexual function index (FSFI) and female sexual distress scale (FSDS) were used to assess sexual function. The assessment was performed before treatment and at 1 month, 2 months and 3 months after treatment. Results: There was a statistically significant decrease in the disease severity starting from 1 month after treatment. At baseline, there was no statistically significant difference between the 2 groups regarding the components of FSFI (except the total score) that was higher in the cases group (P<0.001). However, after treatment all the components of the FSFI were statistically significantly higher in the cases group (P<0.001). The FSDS was statistically significantly higher in the cases group before treatment, after 1 month and after 2 months of treatment (P<0.001), but after 3 months, there was no statistically significant difference (P=0.650). Conclusion: Psoriasis is associated with impairment of the sexual functions in the affected females. The treatment was associated with improvement in the sexual functions, but the modality of treatment didn't affect the sexual function.