This study investigated the indoor application practices of pesticides in different homes located in urban, suburban, and rural areas of the Bangkok Metropolitan Region (BMR). A multi-stage stratified-judgmental sampling was applied to select 280 representative households in BMR for an in-depth questionnaire survey. We found about 71% of these households having mosquitoes as their main indoor nuisance. An inventory on the types and active ingredients was obtained through a shop-shelf survey. Among 22 available commercial products, 12 different active ingredients were observed with the pyrethroid containing pesticides are the most common. The stepwise regression analysis was conducted to reveal the statistical association between indoor levels of total pyrethriods (in the air and on the floor surface of homes) and the household application practices such as the overlap time period since the last application, application and storage locations, and frequency of applications, for instances.