INTRODUCTION: We evaluated performance of transrectal ultrasound-guided systematic (TRUS) biopsy compared to transperineal template mapping (TPM) with a 5mm sampling frame, stratified by MP-MRI Likert score within the PROMIS study. METHODS: Biopsy-naïve men due prostate biopsy for elevated PSA and/or abnormal digital rectal examination underwent MP-MRI, TPM and TRUS biopsies, conducted and reported blind to other test results. Clinically significant prostate cancer (csPCa) was primarily defined as Gleason >/=4+3 or maximum cancer core length (MCCL) >/=6mm of any grade, and secondarily Gleason >/=3+4 or MCCL >/=4mm of any grade. RESULTS: In 41 months, 740 men at 11 centres were recruited; 576 underwent all three tests. Of 150 with MRI score 1-2, 8 (5.1%) had any Gleason >/=3+4 disease on TRUS-biopsy. In 75 where TRUS-biopsy showed Gleason 3+3 of any MCCL, 61/75 (81%) had Gleason 3+4, 8/75 (11%) Gleason 4+3 and 0/75 (0%) Gleason >/=4+5. For definition1 csPCa, TRUS-biopsy sensitivity remained stable and low across MP-MRI Likert scores (35%-52%). For definition2 csPCa and any cancer, sensitivity increased with higher MP-MRI score. Negative predictive value varied due to varying disease prevalence but for all cancer thresholds declined with increasing MP-MRI score. CONCLUSIONS: TRUS-biopsy in the setting of MP-MRI Likert scores 1-2 finds Gleason 3+4 disease in only 1 in 20 men. Further, for any csPCa definition, TRUS-biopsy had poor sensitivity and variable but low NPV across MP-MRI scores. Men undergoing TRUS-biopsy without targeting in the setting of MP-MRI score 3 to 5 should be advised to undergo a repeat (targeted) biopsy.