Electrical injury (EI) is on the rise in the US, with more than 2400 injuries occurring annually. Consequences of EI often include diffuse neurological damage and a myriad of emotional and behavioural sequelae. While delayed onset of cognitive dysfunction is frequently alluded to in the literature, few cases have been published that document the progressive neuropsychological manifestations of EI over time. This paper offers a case study of a 49 year-old female who suffered a high voltage EI and who underwent neuropsychological evaluations at 6 and 56 months post-injury. Comparison of test results suggested a progressive pattern of global decline in cognitive functioning, with particular impairment in memory, verbal learning, abstract reasoning and sensory-motor functions. This case study illustrates the delayed onset and progression of neuropsychological dysfunction that may occur following EI, as well as the importance of long-term follow-up with patients after high voltage EI.