In this study, we attempted to estimate the association between asthma oriented by indoor air sources and personal exposure by comparing the case (asthma-patient) and control (non-asthma-patient) groups. We selected 27 participants who showed positive response on lung function and methacholin provocation test. We performed environmental survey with 15 and 10 cases during May and June 2007, respectively. There was no significant difference between the case and control groups in the level of formaldehyde and TBC (Total Bacterial Count). In the dust allergen test, the case concentration was higher than the control's, without signifiant difference. In the personal exposure assessment of VOCs using OVM (Organic Vapor Monitor) badge, the case concentrations of Benzene, Toluene, and Ethylbenzene were higher than the control's, but there was no significant difference. The personal exposure of Xylene case study was significantly higher than the control's