The diversity and extent of forest in the Itombwe Mountains, eastern Congo Democratic Republic (formerly Zaire), are among the most significance in continental Africa. Despite some human impact, this area still harbors a wide range of vegetation types, including forests and grasslands, drylands and wetlands, and mid-altitude to upper-montane habitats. Forests extend from mid-altitude through sub-montane and montane to alpine zones. These first results provide a general description of the Itombwe Mountains as a basis for more detailed investigations. Certain priorities in conservation-development actions are suggested, based mainly on tree species knowledge; this information could influence further decision-making processes and management guidelines for the conservation and sustainable use of Itombwe's natural resources.