Objective The aim of this study was to determine the prevalence of cognitive impairment (CI) in newly diagnosed and orchiectomized testicular cancer (TC) patients prior to systemic treatment, and to explore biological and psychological correlates. Methods Sixty-six TC patients were compared with 25 healthy men on neuropsychological tests and a measure of cognitive complaints. CI status and a global composite score (representing overall neuropsychological performance) were calculated for each participant. Possible psychological (depression, anxiety, stress, and post-traumatic stress symptoms) and biological (cortisol, IL-6, TNF-α, and CRP) correlates and predictors of patients' cognitive functioning were explored. Results TC patients had lower scores on 6 out of 11 neuropsychological outcomes (p < 0.01) in processing speed, attention, and working memory, verbal learning and memory, and verbal fluency. Prevalence of CI among TC patients was 58%, significantly exceeding the frequency in healthy men (p < 0.01). Patients' cortisol levels predicted overall neuropsychological performance (p = 0.04). Cognitive complaints were associated with IL-6 (p = 0.02) and all psychological distress measures (p < 0.001). Conclusions The prevalence of CI in recently orchiectomized TC patients was unexpectedly high with patients performing more poorly than healthy controls on a majority of neuropsychological outcomes. Cortisol is a potential predictor of neuropsychological performance in TC patients prior to cytotoxic treatment.