Two cases are presented exhibiting temporary increases in sensorineural hearing loss following hearing aid use. Data suggesting this correlation are shown. There were no contributing middle ear problems during the period surveyed. The most significant changes in hearing thresholds were at frequencies 1000 and 2000 Hz. The use of different hearing aids, with decreased maximum power outputs, was not found to have similar effects on hearing threshold levels. A scheduling regime is recommended for introducing any new hearing aid to a child.