The Irish Cancer Society says the HSE's Bowel Screening programme is saving lives.
Latest figures show that almost 197 thousand people were screened between 2012 and 2015 - and 521 cancers were detected.
The initiative targets those between the ages of 60 and 69 - however, just 40% of eligible men and women took part.
Donal Buggy with the Irish Cancer Society says bowel cancer is the second deadliest cancer after lung cancer.
He's pleased with the results so far - but hopes more men will sign up.
"As part of the program over 500 cancers were detected in the early stage", says Mr Buggy.
"Almost 4,300 pre-cancer polyps were detected and removed, so it is catching cancers before they become cancerous."