This paper gives an account of the results achieved in an investigation into the magnitude of lightning currents and voltages on high-voltage transmission lines in Nigeria and describes a continuation of earlier work started by one of the authors. Three-phase oscillographic and klydonographic records of voltages were obtained, together with magnetic link measurements of lightning currents on pole and lattice mast structures. Continuous records have also been obtained of the interchange of current between the earth and atmosphere during disturbed weather conditions.