Introduction: Testicular cancer is a significant malignancy affecting males, and understanding the underlying biochemical changes associated with the disease is essential for improved management and treatment strategies. Prolidase enzyme, has been implicated in various disease processes. The assessment of serum prolidase activity and its relationship with testicular cancer can provide valuable insights into the pathophysiology of the disease. The objective of this study was to investigate serum prolidase activity, oxidative stress markers, and antioxidant enzyme levels in patients with testicular cancer and evaluate their potential associations, aiming to enhance our understanding of the biochemical alterations and potential implications for testicular cancer management. Methods: A total of 33 male patients diagnosed with testicular cancer were included, along with 35 age-matched male volunteers as the control group. Serum samples were collected and stored at −20°C until analysis. The measurement of superoxide dismutase (SOD), glutathione peroxidase (GSHPx), glutathione-S-transferase (GST), malondialdehyde (MDA), glutathione (GSH), and prolidase levels was performed. Results: The findings demonstrated significantly elevated serum prolidase activity and malondialdehyde (MDA) levels in testicular cancer patients compared to the control group (all, p < 0.05). Conversely, superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and glutathione-S-transferase (GST) levels were significantly lower in testicular cancer patients ( p < 0.05). Conclusion: In this study, serum prolidase activity and biochemical markers associated with oxidative stress were investigated in testicular cancer patients. Oxidative stress markers and serum prolidase activity were found to be elevated in testicular cancer. Long-term prospective studies are needed to determine the effectiveness of antioxidant use in cancer treatment.