Restaging local recurrence after high-intensity focused ultra-sound (HIFU) is based on multiparametric MRI (mpMRI). However, postinterventional changes of the tissue, such as edema or hemorrhage, are limiting tumor detection on mpMRI. We present a case of a rising prostate-specific antigen values, negative mpMRI, and a Gleason score of 4+4 on template biopsy after HIFU. On F-choline PET/MR, high focal uptake was detected at the location of positive biopsy. Re-HIFU based on the fused F-choline PET/MR images was performed, followed by a recurrence-free period of 11 months. Thus, F-choline PET/MR could improve guiding retreatment in patients with recurrence after HIFU.