OBJECTIVE: To investigate whether education of primary care professionals improved functional ability in home-dwelling older people, with special focus on gender differences. DESIGN: A prospective controlled three-year follow-up study (1999-2001) with randomisation and intervention at municipality level and outcomes measured at individual level. Intervention municipality visitors received regular education and GPs were introduced to a short assessment programme. Control municipalities received no education but conducted the preventive programme in their own way. SETTING: Primary care, 34 municipalities. SUBJECTS: 5788 home-dwelling 75- and 80-year-olds were invited. 4060 (70.1%) participated: 2104 in 17 intervention- and 1956 in 17 matched control-municipalities. The main outcome measure was obtained from 3383 (95.6%) of 3540 surviving participants. MAIN OUTCOME MEASURE: Functional ability. RESULTS: Municipality intervention in coordination with GPs was associated with better functional ability in women (OR: 1.26; CI95: 1.08-1.47, p=0.004), but not in men (OR: 1.04; CI95: 1.85-1.27). Accepting and receiving free preventive home visits was associated with better functional ability among women (OR: 1.36; CI95: 1.16-1.60, p=0.0002), but not among men (OR: 0.98; CI95: 0.80-1.21). CONCLUSION: A brief, feasible educational intervention for primary care professionals and to accept and receive preventive home visits may have effect in older women, but not in older men.