Background: Australians aged >50 years often experience multiple life changes and challenges, including mental and physical health, work, social, family and financial. This life stage can see adoption of lifestyle choices that can positively or negatively influence health and wellbeing into older age. This study focuses on outcomes relating to psychosocial health and substance use in this cohort, including consideration of social isolation and loneliness. This presentation reports Beyond 50 cohort baseline characteristics. Methods: Baseline cohort of a longitudinal study with annual interview. Baseline sample recruitment occurred September 2023-August 2024. Participants completed a survey including demographics, physical and mental health, social health and substance use measures. Descriptive statistics were used to characterise the sample. Findings: 1059 participants completed valid surveys (median age 62 years, 46.8% female). Just over half (52.4%, n=555) screened positive for hazardous alcohol consumption, 8.7% (n=92) reported recent tobacco use, 3.7% (n=39) reported recent cannabis use and 5.5% (n=58) reported other nonmedical substance use. Twelve percent (n=134) screened positive for symptoms of moderate-severe anxiety, 16.4% (n=174) screened positive for symptoms of moderate-severe depression, 15.7% (n=166) were moderately-severely lonely and 22.6% (n=239) reported being dissatisfied with social relationships. Rates of alcohol use, levels of social isolation, loneliness, anxiety, and depression are comparable to the broader Victoria population. Conclusions: Targeted recruitment strategies resulted in a large, generally representative sample to explore longitudinal decision making and health changes at this important life stage. Future data collection waves with quantitative and qualitative data collection will explore key determinants of healthy ageing.