This　study　attempts　to　collect　more　comprehensive　data　about　the　indoor　environmental　quality　in　urban　dwellings　with　schoolchildren　in　Beijing,　China.　For　this　purpose,　indoor　air　temperature,　relative　humidity　and　the　levels　of　indoor　chemical　and　biological　pollutants　in　14　households　were　measured　in　2013.　Results　show　that,　in　cold　winter,　indoor　relative　humidity　was　often　lower　than　the　comfort　limit　of　30%,　while　indoor　CO2　concentration　was　often　higher　than　the　acceptable　level　of　1000　ppm　in　poorly　ventilated　homes　with　high　occupant　load.　Indoor　PM2.5　pollution　was　very　severe　with　the　highest　level　of　523　mu　g/m(3)　in　living　room　and　345　mu　g/m(3)　in　children＇s　bedroom　in　winter.　Compared　with　the　recommended　thresholds,　the　levels　of　indoor　volatile　organic　compounds　and　carbonyl　compounds　in　most　homes　were　low.　Cigarette　smoke　is　an　important　indoor　source　of　PM2.5,　formaldehyde,　acetaldehyde,　acetone　and　benzene.　Also,　there　are　significant　correlations　between　the　concentration　of　total　volatile　organic　compounds　and　other　compounds　(acetaldehyde,　acetone,　benzene　and　toluene).　Furthermore,　two　phthalates:　di　(2-ethylhexyl)　phthalate　and　di-n-butyl　phthalate　were　frequently　detected　in　house　dust.　Penicillium,　Cladosporium,　and　Aspergillus　were　predominant　fungi　in　indoor　air.　The　fungal　pollution　levels　in　different　seasons　and　rooms　were　also　compared.