Respiratory syncytial virus (RSV) infections in infancy have been related to the subsequent recurrent wheezing and asthma. However, there are a few reports about the relationship between RSV infection and subsequent wheezing in Japan. We sought to determine the contributing factors for wheezing illness after RSV infection in 99 Japanese patients with RSV-associated hospitalizations by questionnaire and follow up survey. Fifty eight patients, who were aged three years old or younger on admission and could be followed up more than one year, were analyzed. The mean duration from discharge to last survey were 703.6+/-105.5 days (432-950 days), the mean age on admission were 9.4+/-8.8 months (0-30 months). Wheezing episodes after discharge were reported in 29 of the subjects (50.0%). Univariable and multivariable analysis identified that the subsequent wheezing after RSV infection were related with the history of wheezing before admission and attending a daycare. The patient's age on admission, the patient's atopic profile, history of continuous nocturnal cough before admission, gestational ages, birth weight, length of hospital stay, perinatal abnormality, environmental tobacco smoke, parental history of allergy and asthma, presence of sibling and sibling history of allergy and asthma were not associated with subsequent wheezing. These results suggest that some host factors susceptible to wheezing and chance of infection due to attending a daycare may be related to recurrent wheezing possibly onset of bronchial asthma, after RSV infection.