Abstract Background Increasing evidence supports the use of magnetic resonance imaging (MRI)-ultrasound fusion–targeted prostate biopsy (MRF-TB) to improve the detection of clinically significant prostate cancer (PCa) while limiting detection of indolent disease compared to systematic 12-core biopsy (SB). Objective To compare MRF-TB and SB results and investigate the relationship between biopsy outcomes and prebiopsy MRI. Design, setting, and participants Retrospective analysis of a prospectively acquired cohort of men presenting for prostate biopsy over a 26-mo period. A total of 601 of 803 consecutively eligible men were included. Interventions All men were offered prebiopsy MRI and assigned a maximum MRI suspicion score (mSS). Men with an MRI abnormality underwent combined MRF-TB and SB. Outcomes Detection rates for all PCa and high-grade PCa (Gleason score GS ≥7) were compared using the McNemar test. Results and limitations MRF-TB detected fewer GS 6 PCas (75 vs 121; p < 0.001) and more GS ≥7 PCas (158 vs 117; p < 0.001) than SB. Higher mSS was associated with higher detection of GS ≥7 PCa ( p < 0.001) but was not correlated with detection of GS 6 PCa. Prediction of GS ≥7 disease by mSS varied according to biopsy history. Compared to SB, MRF-TB identified more GS ≥7 PCas in men with no prior biopsy (88 vs 72; p = 0.012), in men with a prior negative biopsy (28 vs 16; p = 0.010), and in men with a prior cancer diagnosis (42 vs 29; p = 0.043). MRF-TB detected fewer GS 6 PCas in men with no prior biopsy (32 vs 60; p < 0.001) and men with prior cancer (30 vs 46; p = 0.034). Limitations include the retrospective design and the potential for selection bias given a referral population. Conclusions MRF-TB detects more high-grade PCas than SB while limiting detection of GS 6 PCa in men presenting for prostate biopsy. These findings suggest that prebiopsy multiparametric MRI and MRF-TB should be considered for all men undergoing prostate biopsy. In addition, mSS in conjunction with biopsy indications may ultimately help in identifying men at low risk of high-grade cancer for whom prostate biopsy may not be warranted. Patient summary We examined how magnetic resonance imaging (MRI)-targeted prostate biopsy compares to traditional systematic biopsy in detecting prostate cancer among men with suspicion of prostate cancer. We found that MRI-targeted biopsy detected more high-grade cancers than systematic biopsy, and that MRI performed before biopsy can predict the risk of high-grade cancer.