A comprehensive, population-based national indoor air survey was conducted in 2009-2011 in Canada. A total of 84 volatile organic carbons (VOCs) from 3218 houses, 546 apartments, and 93 other dwelling types were measured using passive sampling followed by thermal desorption GC/MS. A total of 12 VOCs were measured in both this study and the 1992 Canadian national study. Arithmetic means of VOCs in this study were 2-5 times lower than those in the 1992 study with the exception of a higher styrene level (1.13 μg · m(-3)). Comparing the geometric means of the 24 VOCs showed that levels for the VOCs in this study were comparable to those reported in Europe. They were generally within a factor of 2; 1,4-dichlorobenzene (0.21 μg · m(-3)) and 1,2,4-trimethylbenzene (0.51 μg · m(-3)) were noticeably lower in this study than in the European studies. There were 47 VOCs detected in more than 50% of Canadian households; 33 of them were higher in houses than in apartments for all nonsmoking homes, while only 4 were lower in houses than in apartments. A total of 11 of 47 VOCs were higher in smoking homes compared to nonsmoking homes, while the rest had similar levels. Principal component analysis identified several groups of VOCs with possible common sources.