The purpose of this study is the outcome evaluation of a small private Early Childhood Development (ECD) program in a developing country focusing on children’s social-emotional adjustment in elementary school. We established a preschool in a slum of the Philippines in collaboration with a local affiliate and proposed a program to promote ECD. It is the program that makes points on promotion of the social emotional development. We evaluated the emotion/behavior of the children who participated in the program from the viewpoints of (1) the short-term outcome at the end of their class and (2) the middle-term outcome when they were in the fourth grade in their elementary school by using the School Mental Health Index and CBCL-TRF. As for the result of (1), improvement was found in terms of the decline observed in the degrees of the “lack of attention/concentration”, “lack of independency” and “uneasiness.” As for (2), We compared the results for the intervention group (n=22), the control group 1 (n=9), and the control group 2 (n= 12). The comparison with the control group shows that the intervention group had fewer emotional/behavioral problems. Following this, we evaluate the ECD program and discuss its effects.