The aim of this study was to find the effectiveness of the Portage Program for Early Intervention in improving cognitive competencies of mothers with children having intellectual disabilities in applying portage program, and in developing those children's adaptive behavior. The experimental sample included 10 children from Irbid Governorate with simple intellectual disabilities, using single-group experimentation. To achieve the goal of the study, the Portage Program (second edition) was adopted as well as the cognitive competence scale for pre and post-test, and the adaptive behavior scale for children with intellectual disabilities. Data from the implemented scales were treated statistically using proper statistical methods. The study reached the following results: There were statistically significant differences at the level of significance ([alpha]=0.05) between the means of the pre- and post-test for performance of mothers of children with simple intellectual disabilities in the cognitive competence scale. There were statistically significant differences at the level of significance ([alpha]=0.05) between the pre- and post-test means for performance of children with simple intellectual disabilities in the adaptive behavior scale. There were statistically significant differences at the level of significance ([alpha]=0.05) between the post and follow up test means for performance of children with simple intellectual disabilities in the adaptive behavior scale. The study sets various recommendations in the fields of education and research. The results of the qualitative analysis indicated a noticeable improvement in the performance of the adaptive behavior skills of the individuals participated in study.