BACKGROUND It is important to clarify the quality of life (QOL) of the asthmatic children and their guardians. METHOD We studied asthmatic patients treated at 359 institutes in Kyusyu and Okinawa, Japan, with QOL questionnaire 2 times in 2001. In the first study, 2906 patients were recruited and 2935 patients were in the 2nd study, and 1563 patients were in both study. RESULT There was a statistically significant relationship, between the QOL and the clinical symptoms in the last 2 weeks, between the QOL and the severity of asthmatic symptoms, and between the patients' or their guardians' QOL and recognition of symptoms. There was a statistically significant relationship between the QOL answered by patients and those by guardians. More significant relationship of QOL between patients' and guardians' was seen in the patients with asthmatic attack or in the severe group, especially in schoolchildren. CONCLUSION Asthmatic control is important for improvement of QOL. Because correlation is significant in QOL between parent and child especially in schoolchildren, asthmatic control is particularly important.