Fewer people now recognise the signs of lung cancer than five years ago.
New research shows 27% of us cannot name a single symptom of the disease.
The Irish Cancer Society says most cases are diagnosed at a late stage, making them difficult to treat.
People are being encouraged to log on to cancer.ie to check their lung health.
Donal Buggy from the Irish Cancer Society says there are some symptoms to watch out for.
He said: "A cough that doesn’t go away, or a feeling of shortness of breath, pain in your chest, feeling more tired than usual.
"If you have any of the symptoms go to your doctor, get seen, get treated and hopefully get well."