Objective Even though the prevalence of mental disorders and social problems is high among elderly patients, it is difficult to detect these in a primary (home) care setting. Goal was the development and preliminary validation of a short observation list to detect six problem areas: anxiety, depression, cognition, suspicion, loneliness, and somatisation. Methods A draft list of indicators identified from a short review of the literature and the opinions of 22 experts was evaluated by general practitioners (GPs) and home care organisations for feasibility. It was then used by GPs and home care personnel to observe patients, who also completed validated tests for psychological disorders (General Health Questionnaire 12 item version (GHQ‐12)), depression (Geriatric Depression Scale 15‐item version (GDS‐15)), anxiety and suspicion (Symptom Checklist‐90 (SCL‐90)), loneliness (University of California, Los Angeles (UCLA)), somatisation (Illness Attitude Scale (IAS)), and cognition (Mini‐Mental State Examination (MMSE)). Results GPs and home care personnel observed 180 patients (mean age 78.4 years; 66% female) and evaluated the draft list during a regular visit. Cronbach's α was 0.87 for the draft list and ≥0.80 for the draft problem areas (loneliness and suspicion excepted). Principal component analysis identified six components (cognition, depression + loneliness, somatisation, anxiety + suspicion, depression (other signs), and an ambiguous component). Convergent validity was shown for the indicators list as a whole (using the GHQ‐12), and the subscales of depression, anxiety, loneliness, cognition, and somatisation. Using pre‐set agreed criteria, the list was reduced to 14 final indicators divided over five problem areas. Conclusion The Observation List for mental disorders and social Problems (OLP) proved to be preliminarily valid, reliable, and feasible for use in primary and home care settings. Copyright © John Wliey & Sons, Ltd.