The correlation between class and delinquency often observed in areal studies and assumed in prominent sociological theories is elusive in studies of individuals commonly used to test these theories. A restricted conceptualization of class in terms of parental origins and the concentration of self-report survey designs on adolescents in school have removed from this area of research street youth who were once central to classic studies of delinquency. We argue that street youth experience current class conditions that cause serious delinquency, and that life on the street is an important intervening variable that transmits indirect effects of control and strain theory variables, including parental class origins. Data gathered from nearly 1000 Toronto school and street youth are analyzed with important implications for the conceptualization of class and delinquency, testing and integrating sociological theories of delinquency, the measurement of delinquency, and the use of cross-sectional and longitudinal research designs. Our findings especially encourage incorporation of street-based samples into research on class-based aspects of theories of delinquency.