It is still debated what is the best early intervention approach for autism. This study compared two intervention approaches, Eclectic-Developmental (ED) and Applied Behavioral Analysis (ABA) in very young children with autism/autism spectrum disorder (ASD). Nineteen children received ED intervention, using combination of methods. Twenty children received Applied Behavioral Analysis (ABA) intervention which used behavioral principles. Children in both groups were not significantly different in their autism severity, cognitive abilities and in socio-economic background at pre-intervention time. Change in the severity of autism symptoms was assessed by the Autism Diagnosis Observation Schedule (ADOS). The ABA group showed significantly greater improvements than the ED group at post-intervention time. Pre-post intervention differences in language and communication domain were significant only for the ABA group. Both groups showed significant improvement in reciprocal social interaction domain. However, the effect size was greater for the ABA group. Changes in diagnostic classification were noted in both groups but were more pronounced for the ABA group. Pre-treatment IQ scores were positively related to ADOS scores at pre- and post-intervention times, but not to progress over time. Behavioral intervention is more effective than eclectic approach in improving autism core symptoms in young children with autism.