Abstract The impact of institutionalization on adoptees’ psychosocial development remains controversial. For shedding light on the influence of pre-adoption history, the rate, and type of behavioral problems in 860 adopted children in all around Norway was examined using Child Behavioral Checklist (CBCL).In the current study, the impact of duration of institutionalization, age at adoption, country of origin, and gender on adoptees behavioral problems were assessed. The results suggest that in general the length of institutionalization is associated with higher rate of internalizing problems and age at adoption was positively linked to behavioral problems in both internalizing and externalizing domains. However, there was a positive but small correlation between duration of institutionalization and adoptees’ internalizing problems. Also, age at adoption generally showed a small positive correlation with adoptee’s internalizing and externalizing behavioral problems. This study also indicates that the country of origin is a significant factor in predicting child behavioral problems so that children adopted from Colombia and Ethiopia demonstrated more behavioral problem than South Korea and China. Finally, the results revealed that adopted boys exhibit more externalizing problem than girls. This research may contribute to more recognition of adoptees’ issues.