This study describes waiting times for cancer treatment in Ireland, tests for differences between health board areas and investigates if delay affected cancer stage or prognosis. We measured the times between referral, outpatient attendance and treatment for all patients diagnosed with five common cancers in Ireland in 1999. There was a four-fold spread of waiting time between the 25th and 75th centile. The time from referral to treatment was shortest for breast cancer (median 4 weeks), twice this for colorectal cancer, lung cancer and lymphoma, and 15 weeks for prostate cancer. Delays varied significantly, but not consistently, between health boards. Patients with longer waiting times generally had less advanced disease and better survival, suggesting that typical delays are not of clinical significance, but that patients with advanced disease are probably being "fast-tracked" by GPs and hospitals.