This case report is of a patient with 46XY pure gonadal dysgenesis, who presented with chronic progressive motor and sensory polyneuropathy. The sural nerve biopsy exhibited minifascicle formations accompanied by a marked decrease in myelinated fibers. This is the first report of polyneuropathy with minifascicle formations in 46XY pure gonadal dysgenesis. Because a similar polyneuropathy was recently reported in a case with 46XY partial gonadal dysgenesis, it is possible that these cases represent a new type of hereditary motor and sensory neuropathy associated with gonadal dysgenesis.