Maintenance can help to prevent the deterioration commonly seen in low-cost buildings in developing countries. Amounts budgeted for maintenance are often inadequate, even when buildings are intended for long-term use. This note aims to increase awareness of the importance of maintenance for low cost housing and other buildings, by explaining how buildings deteriorate, reporting the current maintenance situation in some developing countries, recommending courses of action for maintenance procedures, and good design principles, and examining the economic situation of maintenance. Some of the information is drawn from reports on research projects carried out by South Bank University and the University of Nairobi, specially commissioned for this work.