Lung cancer causes more deaths than any other cancer in Northern Ireland. Survival, and factors which could influence survival, were examined for the 4,458 patients diagnosed with lung cancer from 1992 to 1996. Overall five-year relative survival was low, but better for females (9%) than males (7%). Survival improved each year although this could not be attributed to treatment changes. Survival was better for men under 65 years, than older men (p<0.01), while survival from non-small cell type lung cancer was better than small cell (p<0.001). The proportion of patients having bronchoscopy and CT scan increased over the study period. Although the proportion of patients receiving surgery or radiotherapy remained unchanged over the period there was an increase in the proportion receiving chemotherapy (8.7% vs. 9.4%, P<0.05). Survival rates, although slightly better than in the rest of the United Kingdom, were poorer than in several other countries, including the Republic of Ireland and the United States of America. High mortality rates from lung cancer and, at best, modest improvements in survival, point to the need for increased efforts to reduce levels of lung cancer by tackling the main cause, smoking.