Purpose: To evaluate the relationships between the time spent on sedentary activities (computer usage, video game playing, television viewing, and reading) and physical inactivity in a sample of youth (aged 12-19 years) from the 2000-2001 Canadian Community Health Survey. Methods: The study sample included 7982 youth (4034 males, 3948 females) across Canada (mean age: 15.61 years, SD: 2.23 years). Weekly time spent on computers, video games, television, and reading during leisure-time was obtained through self-reported questionnaires. Physical inactivity was determined by respondents' daily energy expenditure assessed through a physical activity questionnaire. Multivariate logistic regression analysis was conducted to examine the relationship between sedentary activities and physical inactivity respectively by gender. Sociodemographic variables, health status, and overweight status were controlled in the analysis. Results: A substantial proportion of Canadian youth was inactive: 50.3% of males and 67.8% of females. Controlling for sociodemographic variables, health status, and body mass index, television viewing was significantly associated with physical inactivity for both males and females regardless of their overweight status. However, computer usage was associated with physical activity among males, and reading was associated with physical activity among females. Conclusions: There is a complex inter-relationship between sedentary behaviors and physical inactivity, highlighting the need for targeted interventions addressing patterns of sedentary behavior engagement. Reducing time spent on television viewing may be one plausible strategy within such interventions in reducing physical inactivity among youth.