OBJECTIVES: To describe health and functional status in the oldest old; to explore the relationships of morbidity and functional status; and to verify whether this relationship was modified by gender. DESIGN AND SETTING: A community-based survey including all inhabitants aged > or = 90 living in central Stockholm, Sweden. All participants were clinically examined by physicians, cognitively assessed by psychologists, and interviewed by nurses. Diagnoses were made according to the International Classification of Diseases-Ninth Revision (ICD-9), the DSM-III-R criteria for dementia, and Katz index of activities of daily living. PARTICIPANTS: Of the 698 subjects in the study population, 99 (14%) had died and 29 (4%) moved before examination. Of the remaining subjects, 502 (88.1%) were examined, and the refusal rate was 11.9%. MEASUREMENTS: Age- and gender-specific prevalence figures, and age-, gender- and education-adjusted odds ratios (OR) were used. RESULTS: Of 502 examined subjects, 19% had no disease and 73% were functionally independent. Dementia was the most prevalent disease among women (42.2%), and cardio- and cerebrovascular diseases were the most frequent among men (42.4%). Women had higher prevalences of dementia (adjusted OR = 2.1, 95% confidence interval (CI) 1.2-3.7) and fractures and musculoskeletal diseases (adjusted OR = 2.8, 95% CI 1.1-7.3), whereas men had a higher prevalence of malignancy (OR = 0.2, 95% CI 0.1-0.7). Women were more disabled than men independent of age, education, and number of diseases (adjusted OR = 2.2, 95% CI 1.1-4.3). CONCLUSIONS: A great proportion of nonagenarians were functionally independent despite their advanced age. Further studies are needed to clarify the excess of disability among very old women.