BACKGROUND: Diagnosis of cancer as an emergency is associated with poor outcomes but has a complex aetiology. Examining determinants and time trends in diagnostic routes can help to appreciate the critical role of general practice over time in diagnostic pathways for patients with cancer. AIM: To examine sociodemographic, cancer site, and temporal associations with type of presentation among patients with cancer diagnosed as emergencies. DESIGN AND SETTING: Analysis of Routes to Diagnosis data, 2006-2015, for patients with cancer in England. METHOD: The authors estimated adjusted proportions of emergency presentation after emergency GP referral (GP-EP) or presentation to accident and emergency (AE-EP), by patient sex, age, deprivation group, and year of diagnosis using multivariable regression. RESULTS: Among 554 621 patients presenting as emergencies, 24% (n = 130 372) presented as GP-EP, 62% as AE-EP (n = 346 192), and 14% (n = 78 057) through Other-EP sub-routes. Patients presenting as emergencies were more likely to have been GP-referred if they lived in less deprived areas or were subsequently diagnosed with pancreatic, gallbladder, or ovarian cancer, or acute leukaemia. During the study period the proportion and number of GP-EPs nearly halved (31%, n = 17 364, in 2006; 17%, n = 9155 in 2015), while that of AE-EP increased (55%, n = 31 049 to 68%, n = 36 868). CONCLUSION: Patients presenting as emergencies with cancers characterised by symptoms/signs tolerable by patients but appropriately alarming to doctors (for example, pancreatic cancer manifesting as painless jaundice) are over-represented among cases whose emergency presentation involved GP referral. Reductions in diagnoses of cancer through an emergency presentation likely reflect both the continually increasing use of 2-week-wait GP referrals during the study period and reductions in emergency GP referrals.