Abstract Objective: To describe the impact of heavy menstrual bleeding (HMB) and dysmenorrhea on young Australian women’s lives. Design: Cross-sectional online survey. Setting: Australian general population setting. Population: Australian women aged 16-24 with HMB and/or dysmenorrhea. Method: the study was promoted through the online networks of health organisations and community-based groups. Interested parties could opt in (convenience sampling). Data was collected using the secure REDCap platform. Data was analysed descriptively, and associations were explored. Main outcome measures: Prevalence and impact of HMB and dysmenorrhea, information sources, and healthcare-seeking behaviour. Results: 903 participants completed the survey (median age: 22 years, range: 16 - 24, IQR 20-24). All participants reported dysmenorrhea, and 94% (n=554) also had HMB. The most frequent menstrual problems were clots (84%), spotting (34%), and cycle irregularity (51%). Of those who experienced clots (n=497), 70% did so in more than one cycle. Individuals with HMB and dysmenorrhea tend to visit their doctor more than those who with dysmenorrhea alone (p<0.001). The vast majority of participants (92%) were unable to complete daily activities due to dysmenorrhea, and most (69%) also attributed life interference to HMB. Over three-quarters (78%) reported menstruation-related absences from school or university. Participants mostly turned to their mothers (81%), female friends (64%), the internet (61%), and doctors (61%) for information about menstrual health. Youth workers (1%) and male friends (0.7%) were the least common sources of information. Over half (52%) consulted a healthcare professional for menstrual-related issues, but 15% had never done so. Conclusions: Having dysmenorrhea and HMB was disruptive for the daily lives of young women. This was underscored by the lack of reliability and accuracy of their sources of information about menstrual health. There is a need for focused interventions and support systems for this group. Keywords: Young adult, menstrual cycle, menstruation, adolescence, menorrhagia hypermenorrhea, heavy periods, pelvic pain, adolescents, mental health