Background: Results from 12-core template mapping biopsy (Mbx) and concurrent MRI-US fusion targeted biopsy (Tbx) were compared in 118 men without prior biopsy. Methods: Between 12/2012 and 06/2015, 374 men with an indication for prostate biopsy presented to our institution and underwent pre-biopsy mpMRI followed by 12-core standard trans-rectal mapping biopsy (Mbx) and MRI-Ultrasound fusion targeted biopsy (Tbx) of lesions identified on mpMRI. The combination of Mbx and Tbx, when both occurred, constitutes a fusion biopsy (Fbx). Men who underwent both Mbx with or without Tbx using the Artemis/Pro-Fuse system with no previous biopsy were included. Patients without a lesion on MRI underwent Mbx only. Maximum Gleason scores (GS) was assigned on a per patient basis with Mbx GS available for all patients in the cohort and Tbx GS available only for patients with a lesion visible on MP-MRI. Clinically significant (CS) was defined as GS ≥3+4. GS per patient was compared by chi-square and McNemar’s test. Results: 118 men met inclusion criteria (mean age=64.9, mean PSA=11.5). Prostate cancer was detected in 64 (54%) Fbx cases. Cancer detection rates for Mbx and Tbx were 54% and 57%, respectively. In patients where Fbx identified CS cancer, Tbx was more likely to have identified the cancer than Mbx (96% vs 72%; p < 0.001). Fewer GS 6 cancers were detected by Tbx (n=7) than by Mbx (n=25), and Tbx alone would have prevented the detection of 21 (18%) cases of GS 6 disease. Conversely, more GS≥ 7 (50% of men) was detected on Tbx than on Mbx (33% of men). In total, there were 16 patients (13.5%) that were missed or understaged by Tbx, but only 4 of these patients (3%) were GS≥ 7. In contrast, there were 19 (16%) patients that were missed or understaged by Mbx, but 17 (14%) of these 19 patients harbored GS≥ 7 disease. Conclusions: In biopsy-naive men who are suspected to have prostate cancer, Tbx provides improved detection of CS prostate cancer compared with Mbx while decreasing the detection of low-grade disease. Tbx alone in biopsy-naive men should be considered if missing 3% of CS disease is acceptable.