OBJECTIVE To use data from the fourth national survey of morbidity in general practice to investigate the association between home visiting rates and patients' characteristics. METHODS Survey of diagnostic data on all home visits by general practitioners. METHODS 60 general practices in England and Wales. METHODS 502 493 patients visited at home between September 1991 and August 1992. METHODS Home visiting rates per 1000 patient years and home visiting ratios standardised for age and sex. RESULTS 10.1% (139 801/1 378 510) of contacts with general practitioners took place in patients' homes. The average annual home visiting rate was 299/1000 patient years. Rates showed a J shaped relation with age and were lowest in people aged 16-24 years (103/1000) and highest in people aged > or = 85 years (3009/1000). 1.3% of patients were visited five or more times and received 39% of visits. Age and sex standardised home visiting ratios increased from 69 (95% confidence interval 68 to 70) in social class I to 129 (128 to 130) in social class V. The commonest diagnostic group was diseases of the respiratory system. In older age groups, diseases of the circulatory system was also a common diagnostic group. Standardised home visiting ratios for the 60 practices in the study varied nearly eightfold, from 28 to 218 (interquartile range 67 to 126). CONCLUSIONS Home visits remain an important component of general practitioners' workload. As well as the strong associations between home visiting rates and patient characteristics, there were also large differences between practices in home visiting rates. A small number of patients received a disproportionately high number of home visits. Further investigation of patients with high home visiting rates may help to explain the large differences in workload between general practices and help in allocation of resources to practices.