Hospital garden is a type of healing garden or therapeutic landscape as it can offer vital opportunities to contact with nature and have influence upon the mood, stress level, and well-being of users especially patients in need of physical and mental healing. This study was carried out to guide the future planning and design of hospital garden built on the rooftop environment through a Post-Occupancy Evaluation(POE). The roofgarden at Asan Medical Center was evaluated with regards to user's cognition and satisfaction by in-depth interviews and questionnaires. The results are summarized as follows; the users' main behaviors include 'talking', 'resting', 'walking or exercise', 'change of mood', and 'smoking'. The hospital roofgarden was perceived as convenient, and simple space. Factor analysis showed space-images represented by eight factors, 'convenience', 'usefulness', 'maintenance', 'extensity', 'identity', 'crowding', 'privacy', 'complexity'. Rooftop environment was valued for natural setting in artificial construction and users responded affirmatively to 'accessibility', 'view', and. 'fresh air', which were revealed to be factors affecting satisfaction. Changes for the garden such as 'more green shades', 'more seatings', and 'smooth pavement' were requested by users. l11ese research findings make some suggestions; it is necessary to furnish shaded seats for passive behaviors and smooth pathways for a walk or a light exercise. Hospital garden should be designed to provide various visual and functional experiences for patients. Natural shades like tree or pergolas are more desirable than artificial shades giving comfort to the hospital users. For patients and nonsmokers, separated smoking area in the hospital roofgarden would be helpful.