Chronic otitis media (COM) is treated medically and/or surgically. Ossiculoplasty for COM with severe-to-profound hearing loss has not been recommended because the severity of hearing loss before surgery is negatively associated with postoperative hearing improvement. Our study assessed the effectiveness of ossiculoplasty for severe-to-profound hearing loss and identified prognostic factors associated with favorable outcomes. We retrospectively reviewed the medical records of 182 patients with severe-to-profound hearing loss who underwent ossiculoplasty with tympanoplasty and mastoidectomy for COM between January 2017 and December 2018. Air conduction, bone conduction, and air-bone gap significantly improved compared to baseline values. Univariate analysis revealed that high ossiculoplasty outcome parameter staging (OOPS) or middle ear risk index (MERI) scores, obstructed Eustachian tube status, or computed tomography (CT) findings with sclerotic mastoid or soft tissue density (STD) of the retrotympanic space were associated with a lower odds ratio for air gain ≥ 20 dB at 12 months postoperatively. Multivariate analysis revealed that a high OOPS score and obstructed Eustachian tube significantly predicted poorer outcomes. In conclusion, ossiculoplasty can be considered for selected patients with COM, such as those with a low OOPS index, aerated middle ear, or no STD of the retrotympanic space on CT, before cochlear implantation even if they had severe-to-profound hearing loss and high bone conduction threshold.