A major study published in The Lancet followed 162,000 men for 13 years and found screening saved one life for every 781 men regularly screened over this time.
But the researchers from across Europe said the risks of overdiagnosis, which can lead to overtreatment and side-effects such as incontinence and impotence, outweighed the benefits of mass screening.
The NHS does not currently screen for prostate cancer, but PSA testing can be performed on request.
The European Randomised Study of Screening for Prostate Cancer, launched in 1993, recruited men aged 50-74 from Belgium, Finland, France, Italy, the Netherlands, Spain, Sweden, and Switzerland.
Participants were randomised to PSA screening every four years or no screening. Men were referred for biopsy if their PSA concentration exceeded 3.0ng/ml.
After 13 years, there were 13,515 prostate cancer cases among the two groups. Researchers found that men who were screened had a 27% lower risk of dying from prostate cancer than the control group. Screened men were also less likely to develop advanced prostate cancer.
Study leader Professor Fritz Schröder from Erasmus University Medical Center in the Netherlands said: 'PSA screening delivers a substantial reduction in prostate cancer deaths, similar or greater than that reported in screening for breast cancer.
'However, overdiagnosis occurs in roughly 40% of cases detected by screening resulting in a high risk of overtreatment and common side-effects such as incontinence and impotence.
He said: 'The time for population-based screening has not arrived.'
More research was needed on how to reduce overdiagnosis by avoiding unnecessary biopsy procedures, he added.
For now, he said, men must be given well-balanced information including about the screening harms of overdiagnosis and overtreatment.
The UK National Screening Committee does not recommend systematic screening for prostate cancer because the harms 'are currently likely to outweigh the benefits'.
Its last review, in 2010, said PSA was a 'poor test' for prostate cancer and a more specific and sensitive test was needed.