OBJECTIVES: To identify opportunities for reducing emergency colon cancer diagnoses, we evaluated symptoms and benign diagnoses recorded before emergency presentations (EP). METHODS: Cohort of 5,745 colon cancers diagnosed in England 2005-2010, with individually linked cancer registry and primary care data for the 5-year pre-diagnostic period. RESULTS: Colon cancer was diagnosed following EP in 34% of women and 30% of men. Among emergency presenters, 20% of women and 15% of men (p = 0.002) had alarm symptoms (anaemia/rectal bleeding/change in bowel habit) 2-12 months pre-diagnosis. Women with abdominal symptoms (change in bowel habit/constipation/diarrhoea) received a benign diagnosis (irritable bowel syndrome (IBS)/diverticular disease) more frequently than men in the year before EP: 12% vs. 6% among women and men (p = 0.002). EP was more likely in women (OR = 1.20; 95% CI 1.1-1.4), independently of socio-demographic factors and symptoms. Benign diagnoses in the pre-diagnostic year (OR = 2.01; 95% CI 1.2-3.3) and anaemia 2-5 years pre-diagnosis (OR = 1.91; 95% CI 1.2-3.0) increased the risk of EP in women but not men. The risk was particularly high for women aged 40-59 with a recent benign diagnosis vs. none (OR = 4.41; 95% CI 1.3-14.9). CONCLUSIONS: Women have an increased risk of EP, in part due to less specific symptoms and their more frequent attribution to benign diagnoses. For women aged 40-59 years with new-onset IBS/diverticular disease innovative diagnostic strategies are needed, which might include use of quantitative faecal haemoglobin testing (FIT) or other colorectal cancer investigations. One-fifth of women had alarm symptoms before EP, offering opportunities for earlier diagnosis.