Biocides are widely used in our daily life as disinfectants or protection products in building materials. The scientific literature on these substances mainly focuses on outdoor exposure despite the potential threat to people exposed indoors and the lack of information on indoor contamination. The objective of this study was to develop a protocol for biocide monitoring in indoor dust. 18 biocides were selected based on their consumption and their toxicity. The dusts from 12 dwellings were collected during 2021 using a vacuum cleaner equipped with a bag. After sieving at 100 µm, a microwave-assisted extraction was performed twice, followed by analysis by liquid chromatography coupled to a tandem mass spectrometer with internal standards. For the first time, it was shown that 16 out of 18 biocides were observed at least once in household dust. The highest contaminations were found for BAC C16 with 28,000 ng/g and BIT with 3,500 ng/g.