Background: Orphaned children are one of the most vulnerable and needy groups of children all over the world. Those children suffer from the trauma of loss of one or both parents, followed by lacking in satisfaction of their bio- psychosocial needs especially in the care institutions. Aim: Evaluate the effect of developed protocol of care on satisfaction of bio-psychosocial needs of institutionalized school age orphans children. Design: A Quasi- experimental research design. Setting: This study was conducted in three orphanages affiliated to the Ministry of Social Affairs in Tanta city and Kafr El-sheikh city. Subjects: A convenience sample of 60 of the institutionalized school age orphans and 28 of their caregivers were included in this study. Tools: two tools were used. Tool I: Structured interview schedule for institutionalized school age orphans children included three parts, part1): bio-socio demographic data of institutionalized school age orphans children, part2): Assessment of satisfaction of bio psychosocial needs and Part3): Institutionalized school age orphans children observational checklist. Tool II: Structured questionnaire schedule for caregivers included two parts, part1): Socio - demographic characteristics of the caregivers: part2): Caregiver's knowledge about the bio psychosocial needs of institutionalized school age orphans children. Results: There was a statistically significant improvement in the mean score of satisfaction of bio- psychosocial needs among the studied orphan children pre, immediately, and three months post- protocol intervention (P=0.001). Where, the mean scores of their total bio psychosocial needs satisfaction improved from 69.99+6.02 pre-protocol intervention to 92.71+4.01 immediately post and 86.23+4.85 three months post-protocol intervention. Conclusion and recommendations: The protocol of care was effective in satisfying and improving the bio psychosocial needs of the school age orphan children. Therefore, protocol of care should be conducted at all orphanage homes to meet their bio psychosocial needs and to promote a healthier lifestyle among orphan children