Background: Outer hair cells are specialized sensory cells of the mammalian cochlea that contribute to cochlear amplification. Otoacoustic emissions have great potential to detect cochlear impairment, especially in nonlinear mechanical functions of the outer hair cells (OHCs).   Objective: To assess the hearing in normal ear by determining cochlear function, as evaluated by TEOAE and DBOAE in patient with unilateral sensory hearing loss with sudden onset. Patients and Methods: This case control study included study group, which included patients with history of SSNHL with normal ear and control group that included similar number of matched subjects included in the same period with bilateral normal hearing. Every participant was subjected to full audiological history taking, otoscopic examination, pure tone audiometer, immittancemetry and otoacoustic emissions. Results: There was a statistically significant difference among the two groups concerning TEOAE of the left ear frequency in Freq 1.0 NF, Freq 1.0 TE NF, Freq 1.5 NF, Freq 2.0 NF, and Freq 2.0 TE NF, among DBOAE of the right ear in F 1641 DP NF, F2 2016 NF, F 2484 DP NF, F2 3000 NF, F 3281 DP NF, F 4922 DP NF, F 6516 DP NF,F1 609 DP, and F 609 DP NF and among DBOAE of the left ear, F1 4922 DP, F 4922 DP NF, F2 2016 NF, F 1641 DP NF, F2 1500 NF, and F2 750 NF. Conclusion: The study supported the use of otoacoustic emissions as a noninvasive and sensitive tool for assessing cochlear health, particularly in cases of sudden hearing loss.