Thermal desalination plants have been operating in Libya since 1975. Over this period, the total installed capacity has grown to more than 330,000m(3)/d. Of this, more than 300,000m(3)/d are produced by multi-stage flash (MSF) and the rest by multi-effect distillation (MED). This paper describes a complete survey of all installed thermal desalination plants which are operated by The General Electric Company of Libya (GECOL) from 1975 to 2000, and also describes the problems encountered in the past and the adapted solutions for some of these problems.