Medical laboratory services are an essential, yet often neglected, component of health systems in developing countries. Their central role in public health, disease control and surveillance, and patient management is often poorly recognized by governments and donors. However, medical laboratory services in developing countries can be strengthened by leveraging funding from other sources of HIV/AIDS prevention, care, surveillance, and treatment programs. Strengthening these services will require coordinated efforts by national governments and partners and can be achieved by establishing and implementing national laboratory strategic plans and policies that integrate laboratory systems to combat major infectious diseases. These plans should take into account policy, legal, and regulatory frameworks; the administrative and technical management structure of the laboratories; human resources and retention strategies; laboratory quality management systems; monitoring and evaluation systems; procurement and maintenance of equipment; and laboratory infrastructure enhancement. Several countries have developed or are in the process of developing their laboratory plans, and others, such as Ethiopia, have implemented and evaluated their plan.