OBJECTIVE: To describe the occurrence of mental health problems and cognitive impairment in a group of elderly homeless men and to demonstrate how clinical examination and screening tests used in a shelter setting might be helpful in identifying mental illness and cognitive impairment. DESIGN: Cross-sectional study including face-to-face interviews and review of medical records. SETTING: A community-based homeless shelter in an urban metropolitan centre (Toronto, Ont). PARTICPANTS: A total of 49 male participants 55 years of age or older. The average duration of homelessness was 8.8 (SD 10.2) years. METHODS: Participants were admitted to a community-based shelter that offered access to regular meals, personal support and housing workers, nursing, and a primary care physician. Medical chart review was undertaken to identify mental illness or cognitive impairment diagnosed either before or after admission to the facility. The 15-item Geriatric Depression Scale (GDS-15) and the Folstein Mini-Mental State Examination (MMSE) were administered. MAIN OUTCOME MEASURE: Previous or new diagnosis of mental illness or cognitive impairment. RESULTS: Thirty-six of the participants (73.5%) had previous or new diagnoses. The most prevalent diagnosis was schizophrenia or psychotic disorders (n = 17), followed by depression (n = 11), anxiety disorders (n = 3), cognitive impairment (n = 8), and bipolar affective disorder (n = 1). A total of 37% of participants were given new mental health diagnoses during the study. The GDS-15 identified 9 people with depression and the MMSE uncovered 11 individuals with cognitive impairment who had not been previously diagnosed. CONCLUSION: This study suggests that providing access to primary care physicians and other services in a community-based shelter program can assist in identification of mental illness and cognitive impairment in elderly homeless men. Use of brief screening tools for depression and cognitive impairment (like the GDS-15 and the MMSE) could be helpful in this highrisk group.