Among people with prostate cancer, transgender women receiving estrogen are more likely to present with high-grade disease vs cisgender men, suggesting potential delayed diagnosis.1 A possible reason for delayed diagnosis may be the absence of prostate-specific antigen (PSA) reference ranges specific to transgender women receiving gender-affirming hormones. Due to the castrating effects of gender-affirming hormones, PSA, whose production is androgen-regulated,2 would be expected to be lowered. This study determined PSA values among a nationwide cohort of transgender women without known prostate cancer receiving estrogen, the most common gender-affirming hormone.