A staged model of smoking adoption has been widely applied in studies of adolescent smoking. The present study applied this model to examine the preliminary stages of tobacco and alcohol use by children. Using discriminant analysis, factors associated with the abstinence, initiation, and experimentation stages of tobacco and alcohol use were compared in a sample of 1,272 children in grades 4 and 6. Modeling of use by best friends and the perceived prevalence of use among same-age peers were most strongly related to the initiation and experimentation stages of tobacco and alcohol use. Other key factors were offers from parents and friends, adjustment to school, and behavioral self-regulation. The weakest factors were parental modeling and self-esteem. The initiation and experimentation stages are not as highly differentiated among children as other studies have found them to be among adolescents, suggesting that if initiation occurs during childhood, progression to experimentation is likely. Prevention programs could simultaneously influence children's risk of tobacco and alcohol use by targeting the common risk factors for preliminary use of these substances.