This study examined the effects of a computer-based early reading program (Headsprout Early Reading) on the oral language and early reading skills of at-risk preschool children. In a pretest-posttest control group design, 62 children were randomly assigned to receive supplemental instruction with Headsprout Early Reading (experimental group) or Millie's Math House (control group) for 30 min each school day for 8 weeks. Children using Headsprout Early Reading made greater gains in early reading skills as measured by the Test of Early Reading Ability (TERA-3), F(1, 59) = 39.35, p less than 0.01, and in oral language skills as measured by the Test of Language Development-Primary (TOLD-P:3), F(1, 59) = 37.03, p less than 0.01. Effect sizes were large for the gains in both measures (TERA-3, eta[superscript 2] = 0.24; TOLD-P:3, eta[superscript 2] = 0.17). Teachers' responses to an open-ended interview indicated that the program was perceived as a desirable instructional aid. Educational considerations for preventing future reading difficulties and issues about implementation integrity are discussed. (Contains 5 tables.)