Although most primary health care teams in the U.K. now offer proactive care for patients with asthma, there is relatively little published evidence showing the effectiveness of such innovations. This may be due in part to lack of targeting of extra care towards those most in need. Therefore, to demonstrate the benefits of targeted nurse-run asthma clinic care in a seven-partner general practice in a mixed urban and rural area of North Lincolnshire in the east of England, a cohort of 173 patients, with asthma selected predominantly by having high morbidity in a postal survey, completed 12 months follow-up in a nurse-run asthma clinic. A longitudinal comparison was conducted in terms of: changes in morbidity index category, inhaler technique score, knowledge score, use of inhaled steroids, use of salmeterol, method of administration of beta(2)-agonist medication and frequent use of peak flow meters. The number with high morbidity fell from 123 (71.1%) at the initial consultation to 14 (8.1%) at the 12-month review. Those with full marks on inhaler technique rose from 28 (16.2%) to 142 (82.1%), and with full marks on asthma knowledge rose from 7 (4.0%) to 98 (56.6%). The numbers of patients using inhaled steroids and salmeterol rose from 127 (73.4%) to 171 (98.9%) and from 5 (2.9%) to 35 (20.2%), respectively. The preferred inhaler device for beta(2)-bronchodilator medication changed from metered dose aerosol to dry powder. Regular use of peak flow meters in 157 subjects aged 5 years and over rose from 43 (27.4%) to 116 (73.9%). These data clearly demonstrate the benefits of targeted proactive nurse-run asthma care in terms of reduced morbidity for patients. The authors recommend the morbidity index targeting concept to other primary health care teams.