We report a case of unilateral auditory neuropathy (AN) showing improvement in both pure tone hearing (PTA) and speech discrimination scores (SDS) with time. Some reports have documented the findings of auditory examination in patients with unilateral AN, and a few reports have documented the time-related changes in these findings for the same patients. A 3-year-old Japanese boy was referred to our hospital for audiological evaluation of his left ear. The audiogram showed normal hearing threshold in his right ear and severe sensorineural hearing loss in the left ear. DPOAE testing showed normal bilateral responses. ABR in the left ear showed no response of any waves in 110 dB hearing level, whereas the electrocochleogram (ECochG) showed broad compound action potentials (CAP) and the absence of N2. PTA and SDS at age 4 revealed slight improvement in the hearing threshold in the left ear.