Health concerns and the cost are the two main reasons why smokers want to kick the habit, according to data from the National Smokers Quitline.
Today is national No Smoking Day.
The Irish Cancer Society said smokers should also think of their children's health as passive smoking can result in respiratory problems.
Consultant respiratory physician at Temple Street Children's Hospital in Dublin Dr Fiona Neary said: "We know that 25% of people who live in Ireland smoke and up to a third of cancers can be caused by smoking.
"In relation to children, we know that those exposed to second-hand smoke alone are at risk of respiratory diseases, particularly asthma. We also know there's an increased risk of lung cancer in later life."