Healthy buildings are important as most people need well-constructed houses for their daily lives and durable houses to avoid accidents which may happen as well as the destruction of the houses. Therefore, this study examined the concept of housing transformation and rehabilitation in Biryogo Cell, City of Kigali for healthy buildings and climate-resilient cities. Interviews with 50 residents of Kigali city and One (1) Senior Engineer in the Infrastructure Department in Kigali city were done to capture views on the concept of housing transformation and rehabilitation as well as their impact on healthy buildings contrary to previous forms of old houses. Additionally, 30 site visits and observations have proven current development achievements. Results demonstrated that 91% Biryogo cell residents see housing transformation and rehabilitation as a helpful influence by giving an opportunity for durable houses, an increase in land value, and saving more land for additional uses. Housing development professionals responded that housing transformation and rehabilitation impacted suitable land uses and changes in the city. Despite these advantages, the concept is limited with insufficient financial capability to ease the idea of housing transformation and rehabilitation. Houses that result from housing rehabilitation and transformation are those located on asphalt roads in Biryogo cell. Car-free zones are also well-provided and connected to other roads including the main road from and to the City Center for smooth accessibility. Hence, this study will have much contribution on houses by increasing healthy buildings and climate-resilient cities in developing and developed world. These housing transformation and rehabilitation considered Four (4) components of sustainability which are human, social, economic, and environmental. The study recommends the concept of housing transformation and rehabilitation in informal settlements exposed to destruction for future climate-resilient cities.