To provide new information on factors associated with discrepancies between patient-reported and audiometrically defined hearing loss (HL) in adult-onset cancer survivors after cisplatin-based chemotherapy (CBCT) and to comprehensively investigate risk factors associated with audiometrically defined HL. A total of 1410 testicular cancer survivors (TCS) ≥6 months post-CBCT underwent comprehensive audiometric assessments (0.25 to 12 kHz) and completed questionnaires. HL severity was defined using American Speech-Language-Hearing Association criteria. Multivariable multinomial regression identified factors associated with discrepancies between patient-reported and audiometrically defined HL and multivariable ordinal regression evaluated factors associated with the latter. Overall, 34.8% of TCS self-reported HL. Among TCS without tinnitus, those with audiometrically defined HL at only extended high frequencies (EHFs) (10 to 12 kHz) (17.8%) or at both EHFs and standard frequencies (0.25 to 8 kHz) (23.4%) were significantly more likely to self-report HL than those with no audiometrically defined HL (8.1%) [odds ratio (OR) = 2.48; 95% confidence interval (CI), 1.31 to 4.68; and OR = 3.49; 95% CI, 1.89 to 6.44, respectively]. Older age (OR = 1.09; 95% CI, 1.07 to 1.11, p < 0.0001), absence of prior noise exposure (OR = 1.40; 95% CI, 1.06 to 1.84, p = 0.02), mixed/conductive HL (OR = 2.01; 95% CI, 1.34 to 3.02, p = 0.0007), no hearing aid use (OR = 5.64; 95% CI, 1.84 to 17.32, p = 0.003), and lower education (OR = 2.12; 95% CI, 1.23 to 3.67, p = 0.007 for high school or less education versus postgraduate education) were associated with greater underestimation of audiometrically defined HL severity, while tinnitus was associated with greater overestimation (OR = 4.65; 95% CI, 2.64 to 8.20 for a little tinnitus, OR = 5.87; 95% CI, 2.65 to 13.04 for quite a bit tinnitus, and OR = 10.57; 95% CI, 4.91 to 22.79 for very much tinnitus p < 0.0001). Older age (OR = 1.13; 95% CI, 1.12 to 1.15, p < 0.0001), cumulative cisplatin dose (>300 mg/m2, OR = 1.47; 95% CI, 1.21 to 1.80, p = 0.0001), and hypertension (OR = 1.80; 95% CI, 1.28 to 2.52, p = 0.0007) were associated with greater American Speech-Language-Hearing Association-defined HL severity, whereas postgraduate education (OR = 0.58; 95% CI, 0.40 to 0.85, p = 0.005) was associated with less severe HL. Discrepancies between patient-reported and audiometrically defined HL after CBCT are due to several factors. For survivors who self-report HL but have normal audiometric findings at standard frequencies, referral to an audiologist for additional testing and inclusion of EHFs in audiometric assessments should be considered.