We evaluated outcomes for 31 children with autism (2-6 years of age at intake) who received behavioral intervention in mainstream pre-school settings and a comparison group of 12 children receiving treatment as usual. After 2 years, children receiving behavioral intervention had higher IQ scores (Hedges g = 1.03 (95% CI = 0.34, 1.72) and adaptive behavior composite scores (Hedges g = 0.73 (95% CI = 0.05, 1.36). Despite probably fewer intervention hours, these group level outcomes were comparable to studies providing more intensive intervention. Individual child data also showed positive results with 19.4% achieving change at a reliable level for IQ; but a lower percentage than found in recent meta-analysis research. Strengths and weaknesses of the mainstream pre-school delivery model are discussed. (Contains 4 tables and 1 figure.)