<p>The aim of the present study was to measure the concentrations of benzene, toluene, ethylbenzene and xylene in the indoor and outdoor air of houses in Borazjan (Iran) and to estimate the risks of these compounds. Indoor and outdoor air samples (40 and 20, respectively) from various urban locations were analyzed using gas chromatography with a flame ionization detector. The mean concentrations of benzene, ethyl benzene, o-xylene, p-xylene, and m-xylene in the indoor air of homes were 4.48, 0.37, 9.15, 1.12, and 0.68 μg/m³, respectively. Also, the concentrations of these compounds in the outdoor air were 10.99, 0.01, 8.67, 3.05 and 2.99 μg/m³, respectively. The amount of toluene in all samples was reported to be lower than the detection limit of the device. The carcinogenic risks for benzene was higher and for ethylbenzene was lower than 1 × <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({10}^{-6}\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mn>10</mn> </mrow> <mrow> <mo>-</mo> <mn>6</mn> </mrow> </msup> </math></EquationSource> </InlineEquation>. Also, the non-carcinogenic risk for all compounds was reported to be less than 1. Benzene, toluene, ethylbenzene and xylene concentrations in indoor air were lower than those in outdoor air, likely because closed doors and windows partially obstruct the entry of polluted air from outside. Also, indoor air purification by split air conditioners may contribute to this difference. Factors that overall impact benzene, toluene, ethylbenzene and xylene levels within the building include the garage attached to the house, renovation of the house, presence of furniture, grilling of food in the kitchen, use of insecticides, the distance from the house to the main street, and length of living in the residence.</p>