Objective: Understanding patients' personal characteristics is essential for better asthma management. This study assessed the relationships between patients' related variables in asthma and identified key associations relevant to asthma management. Methodology: Subjects were recruited from the Alfred Hospital Asthma and Allergy Clinic (Melbourne, Victoria, Australia) and general practices. Their clinical and demographic characteristics, asthma knowledge, impact of asthma on their quality of life, their self-management skills and attitudes to asthma were assessed. Results: One hundred and sixty-nine subjects participated in the study. Fifty-seven per cent had one or more previous hospital admissions, 94% had either moderate or severe asthma, and 51% reported nocturnal symptoms in the last 6 weeks. Patients who spoke only English, had been admitted to an intensive care unit, had a peak flow meter, and an asthma action plan had significantly better asthma knowledge than those who did not. The impact of asthma was greatest in patients who had a peak flow meter, used oral steroids, had exercise limitation, and developed asthma between the ages of 31-45 years. Female patients had better self-management skills than males. Patients with asthma-related distress were more likely to use oral steroids or theophylline and to have a history of previous hospital admissions. Patient self-confidence was negatively correlated with age. Conclusions: There are significant relationships between many of patients' variables related to asthma, including their personal clinical, demographic and psychological characteristics. The findings have implications for optimizing asthma management.