Abstract Background High urinary activity in urinary bladder and ureters may hamper interpretation of prostate cancer and regional nodal metastases in prostate-specific membrane antigen (PSMA) PET/CT. The goal of this study was to assess effects of furosemide and choice of tracer on urinary activity in the bladder and ureters, as well as on occurrence of peri-bladder artefacts in PET/CT. Methods Four cohorts with a total of 202 men staged with PSMA PET/CT for prostate cancer received either 68Ga-PSMA-11 as tracer, with (cohort G+) or without 10mg intravenous furosemide (G−) concurrent with tracer, or 18F-DCFPyL with (F+) or without furosemide (F−). SUVmax of bladder and ureters, presence, type, and severity of peri-bladder artefacts were compared between cohorts. The influence of furosemide and choice of tracer was determined while taking differences in biodistribution time into account. Results Median SUVmax bladder was 43,5; 14,8; 61,7 and 22,8 in cohorts G−, G+, F− and F+, respectively, resulting in significant overall (p