Background: Men with germline BRCA1/2 mutations have a higher risk of developing prostate cancer (PrCa) than non-carriers. IMPACT is an international consortium of 62 centers in 20 countries evaluating the use of targeted PrCa screening in men with BRCA1/2 mutations. This analysis reports the first year’s screening results for all men at enrolment in the study. Methods: We recruited men aged between age 40 and 69 with germline BRCA1/2 mutations and a control group that tested negative for a BRCA1/2 mutation. All men underwent prostate-specific antigen (PSA) testing at enrollment and those with a PSA of greater than 3ng/ml threshold were offered prostate biopsy. All men are offered a biopsy irrespective of PSA level after five years of screening. Results: We recruited 2,481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls) of whom 199 (8%) presented with a PSA greater than 3ng/ml. We performed a total of 162 biopsies and diagnosed 59 PrCas (18 BRCA1 carriers, ten BRCA1 controls; 24 BRCA2 carriers, seven BRCA2 controls); 66% of the tumors were classified as intermediate or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3·0ng/ml in BRCA2 mutation carriers was 48%, double that reported in population screening studies. A significant difference in detecting intermediate or high-risk disease was observed in BRCA2 carriers using this threshold. Conclusions: The IMPACT screening network will be useful for targeted PrCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this yields a high proportion of aggressive disease. Early data indicate that the majority of BRCA1/2 mutation carriers diagnosed with prostate cancer at biopsy had developed clinically significant disease (requiring radical treatment). Clinical trial information: NCT00261456.