Abstract Objective Prostate cancer is the most common malignancy among men and following a positive prostate‐specific antigen (PSA) screening test, patients may undergo more expensive diagnostic testing. However, testing‐related out‐of‐pocket costs (OOPCs), which may preclude patients from completing the screening process, have not been previously quantified. OOPCs for follow‐up diagnostic testing (i.e., prostate biopsy and/or magnetic resonance imaging [MRI]) in patients with private insurance undergoing prostate cancer screening were estimated. Methods Men ages 55 to 69 years old who underwent PSA‐based prostate cancer screening from 2010 to 2020 from the IBM Marketscan database were identified. The number of patients undergoing follow‐up diagnostic testing within 12 months of screening was tabulated, dividing patients into three groups: (1) biopsy only, (2) MRI only, and (3) MRI + biopsy. Over the study period, patients with nonzero cost‐sharing and calculated inflation‐adjusted OOPCs, adding copayment, coinsurance, and deductible payments, for each group were identified. Results Among screened patients ( n = 3,075,841) from 2010 through 2020, 91,850 had a second PSA test and an elevated PSA level, of which 40,329 (43.9%) underwent subsequent diagnostic testing. More than 75% of these patients experienced cost‐sharing, and median OOPCs rose substantially over the study period for patients undergoing biopsy only ($79 to $214), MRI only ($81 to $490), and MRI and biopsy ($353 to $620). Conclusions OOPCs from diagnostic testing after prostate cancer screening are common and rising. This work aligns with the recent position statement from the American Cancer Society, that payers should eliminate cost‐sharing, which may undermine the screening process, for diagnostic testing following cancer screening.