OBJECTIVE: To analyse the trends in opportunistic PSA screening in Australia, focusing on younger men (<55 years of age), to examine the effects of this screening on transrectal ultrasonography (TRUS)-guided biopsy rates and to determine the nature of prostate cancers (PCas) being detected. SUBJECTS AND METHODS: All men who received an opportunistic screening PSA test and TRUS-guided biopsy between 2001 and 2008 in Australia were analysed using data from the Australian Cancer registry (Australian Institute of Health and Welfare) and Medicare databases. The Victorian cancer registry was used to obtain Gleason scores. Age-standardized and age-specific rates were calculated, along with the incidence of PCa, and correlated with Gleason scores. RESULTS: A total 5 174 031 PSA tests detected 128 167 PCas in the period 2001-2008. During this period, PSA testing increased by 146% (a mean of 4629 tests per 100 000 men annually), with 80 and 59% increases in the rates of TRUS-guided biopsy and incidence of PCa, respectively. The highest increases in PSA screening occurred in men <55 years old and up to 1101 men had to be screened to detect one incident case of PCa (0.01%). Screening resulted in two thirds of men aged <55 years receiving a negative TRUS biopsy. There was no correlation with Gleason >7 tumours in patients aged <55 years. CONCLUSION: Despite the ongoing controversy about the merits of PCa screening, there was an increase in PSA testing, especially in men <55 years old, leading to a modestly higher incidence of PCa in Australia. Overall, PSA screening was associated with high rates of negative TRUS-biopsy and the detection of low/intermediate grade PCa among younger patients.