The goal of this study was to evaluate the effects of four kinds of day-care services on the language development of 306 children in a half-time junior kindergarten program in a French language Ontario school board. The children attended four types of child-care services: home day-care by one of the parents (N=136), home daycare by a babysitter (N=34), day-care at the home of a babysitter (N=81) and day-care services (N=55). Language was evaluated with the Peabody Picture Vocabulary Test, the French Canadian version of the Test for Auditory Comprehension of Language, questionnaires geared to the teachers (Early Development Instrument) and parents (French usage scale). The results show that children who go to a day-care centre or who stay at home with a babysitter acquire a level of language and vocabulary development globally superior to that of children who stay at home with a parent or who go to a babysitter’s home. Some factors that may explain the differences among these groups are the amount and type of attention and stimulation, the environment and types of activities, and the type of language used.