A total of 554 deaths by suicide were recorded in 2011, 59 more than 2010 and the highest figure since 2001.
Statistics compiled from coroners' reports by the Central Statistics Office show that 458 men and 96 women died by suicide in 2011.
Almost 83% of the suicides were by men.
The highest rates were reported among men aged between 45 and 64, and women in the 25-44 age group.
The report also reveals that men are more than five times more likely to take their own lives.
Greece and Cyprus have the lowest suicide rates in the European Union, with Lithuania, Hungary and Latvia reporting the highest.