This is an appraisal of the performance of the four 75 MW gas turbines (GTs), i.e. the first large-power generating GTs installed in Nigeria. All the major parameters considered-availability, utilization and capability factors-were much lower than acceptable. The frequency of failures of some vital components of the machines is also higher than normal. The general low performance is linked to some peculiar environmental conditions of the place and circumstances of the country, which make the design of certain parts of the GTs inadequate.