More than 10,000 members of the Irish Nurses and Midwives Organisation will be eligible to avail of a Free Breast Health Assessment service from today.
The 'Pink Power' initiative is the first of its kind in the Irish trade union movement.
Last year, 26% of all INMO claims were for cancer, with breast cancer accounting for more than half.
The INMO said it is a particularly pertinent move for the union which has a mostly female membership.
A Prostate and Testicular Cancer assessment will also be available to men.