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Background: Prostate cancer (PCa) patients with biochemical recurrence (BCR) following radical prostatectomy or radiation therapy often present with very low prostate-specific antigen (PSA) levels (⩽0.5 ng/mL). Accurate detection of recurrence at such low levels is crucial for guiding treatment decisions. Objectives: To assess the diagnostic efficacy of [ Design: A prospective study conducted between May 2021 and January 2023, with data subsequently analyzed retrospectively after a 2-year follow-up. Methods: The cohort comprised 157 PCa patients with BCR, of whom 52 had PSA levels ⩽ 0.5 ng/mL and underwent PSMA-PETMR imaging. The imaging protocol incorporated multiparametric MRI (mpMRI) and PET acquisitions, with lesion classification following PSMA-RADS version 1.0. Detection rates of recurrent lesions, including local recurrence, lymph node metastasis, and skeletal metastasis, were evaluated. Results: PSMA-PETMR exhibited a 63.5% detection rate for recurrent PCa at low PSA levels, surpassing traditional diagnostic methods. Thirty-four local recurrences, 12 metastatic lymph nodes, and 4 skeletal metastases were identified. Follow-up imaging enhanced the detection rate to 73.1% by reclassifying initially equivocal findings. PSMA-PETMR influenced clinical decision-making in 17% of patients by facilitating personalized treatment strategies. Conclusion: PSMA-PETMR significantly improves the detection of recurrent PCa in patients with very low PSA levels, offering precise lesion localization and supporting personalized treatment approaches. Further studies are needed to optimize its clinical use and validate its long-term benefits.