Current behavioral researches demonstrate that physical environments, i.e., patient rooms and hospitalization space have strong psychological effects on children conditions and cause them some behavioral changes. Since children are usually unfamiliar with medical environments, being in such places can cause some sort of stress and anxiety in them. Therefore, designing less-stressed environments for diseased children seems essential. Accordingly in this paper, we provide an assessment of requirements which are needed in the designing of a friendly space for pediatric in hospital. The paper also aims to find practical ways in establishing desired medical environments according to the children’s need. The research framework is based on Iran as a case study. Similar studies and upcoming trends are reviewed and analyzed. Based on the analyzed data, a domestic study is done on 35 diseased children in the age of 6-12 who have already experienced hospital environment and also on 35 controls who have no previous experience of such environments. Each child is requested to draw pictures about the requirements and the optimal environment which they have considered for a hospitalization space in hospital and researcher helped the children to complete their paintings and express their needs using deep open semi-structured conversation .The time for children was not limited and the children were given a sheet of paper and 12 colored pencil (yellow, red, blue, orange, pink, purple, cream, brown, White, Black, Green, Gray). In addition interviews and questionnaire are conducted from children and children’s parents in hospital. At the end, items extracting from the drawings are investigated in qualitative manner with Atlas Ti 6. All parts of the drawings are coded and then some of the “highly significant” data are investigated quantitatively. Therefore, 8 major themes were extracted from paintings and comments, which were categorized into 2 groups. First group is children needs relevant to physical environment contains entertaining factors, decoration, view, furniture-equipment and second group is children needs relevant to psychological environment contains children relations with family and friends, privacy feeling, safety feeling, cultural- regional- native interests. The finding show that using children’s experience have an important role to put quality to treatment environments and reveals the need of specific pattern in patient room design for children hospital, optimally suitable for diseased children. The analysis also indicates that cultural background has effects on what children expect as their optimal patient room and hospitalization space but also on what they need (in both 2 groups). Therefore, according to the obtained results, it is suggested to use natural elements (plants, natural light, aquarium and...), entertaining devices, attractive images and decoration, happy colors and cultural and regional factors in designing hospitalization spaces for children, and also some places to meet family and friends, making facilities for parents especially mothers in hospital room and next to child's bed, making personal territory and boundaries in hospitalization spaces and especially in the room, making some places for playing, providing some spaces to place children's personal properties and finally some places to meditate in hospital spaces should be considered.