INTRODUCTION: The COVID-19 pandemic can cause emotional distress, which can in turn lead to the development of mental and physical symptoms. AIM: We examined the association of the COVID-19 outbreak and the mental, physical and sexual health of the female Polish population. METHODS: Data were collected in an online survey distributed on social media from April 22, 2020 through to May 7, 2020. The data collection began one month after the start of lockdown in Poland. MAIN OUTCOME MEASURE: Women were asked to complete the Beck Depression Inventory (BDI) and the Female Sexual Function Index (FSFI) questionnaires. RESULTS: Overall, 1644 women (median age 23 years) took part in the survey. They reported a lower frequency of sexual activity (P < .001) and a lower libido level (P < .001) during the pandemic then before it. 57.5% of the study group (n = 944) strongly agreed or agreed that fear of the health condition of loved ones was a source of stress and depressed mood. The average BDI-II total score was 11 (range 0-51; IQR 5-18), which corresponds to minimal depression. The average FSFI total score was 27.01 ± 7.61 (range 2-36). The FSFI and BDI scores were significantly correlated (P < .001). The FSFI score was significantly correlated with the presence of any comorbid chronic disease, the intensity of the fear of infection and fear of health conditions, perceived loneliness, and the being up to date with media news. The BDI score was significantly correlated with age, the intensity of the fear of infection and fear of health conditions, perceived loneliness, being up to date with media news, and the more frequent use of stimulants. CONCLUSIONS: The COVID-19 lockdown setting was associated with a high occurrence of depressive symptoms and increased risk of sexual dysfunction with decreased libido and lower sexual frequency the most commonly reported issues. Szuster E, Kostrzewska P, Pawlikowska A, et al. Mental and Sexual Health of Polish Women of Reproductive Age During the COVID-19 Pandemic - An Online Survey. Sex Med 2021;XX:XXXXXX.