Objectives: Underpinning standards for delivering comprehensive care in hospital is the need to identify issues contributing to patient complexity and risk of harm. The study aimed to investigate the prevalence of functional and psychosocial problems in hospitalized adults, to compare prevalence rates across age groups, and to assess their impact on discharge outcomes. Design, setting, and participants: A prospective cohort study was conducted in 4 hospitals in Australia during September 2015 to June 2016, recruiting patients aged 18 and over. Measures: Research nurses assessed patients at admission using the interRAI Acute Care instrument, which includes algorithms for diagnostic and risk screening and measuring problem severity. Length of stay and discharge outcome were recorded from medical records. Results: The median age of the study population (n = 910) was 66 (range 18-99 years), and 47.7% were female. Although 64.6% of patients aged ≥70 years had at least 1 classic geriatric syndrome (cognitive impairment, dependency in activities of daily living, history of falls, or incontinence), similar problems were prevalent in younger cohorts (34.6% in those aged <50 and 38.9% in those aged 50-69 years). Of 17 health issues assessed across multiple domains, only 26 patients (2.9%) had no problems. Independent of age, gender, and Comorbidity Index, having a greater number of problems was significantly associated with an adverse discharge outcome, odds ratio 1.19 (95% confidence interval (CI) 1.09-1.29); for each additional problem, the length of stay increased by 6.7% (95% CI 4.3%-9.2%). Conclusions/Implications: The high prevalence of functional and psychosocial problems across the age range of patients indicates that universal screening and assessment is warranted for all adult patients to aid in care planning to meet patient needs both in acute care and post discharge.