Background: Little is known about “within-patient delay”, time from first symptom of lung cancer to contacting primary care. Aim: Primary outcomes were length of within-patient delay and the proportion of total delay it represents. Secondary outcomes were factors causing delay and survival. Design and Setting: Newly diagnosed lung cancer oncology patients at two hospitals in Norfolk. Method: Patients completed questionnaires regarding onset of symptoms, whether they had delayed, and their reasons. GPs completed correlating questionnaires. Pathway times and other data were extracted from cancer registry and hospital records and outcomes obtained prospectively. Factors causing delay were compared using ratios of geometric means. Results: In 379 patients, mean within-patient delay and pre-secondary care delay were 188.6 and 241 days (61.4% and 78.5% of total delay respectively). 38.8% patients felt they had delayed. Patient-related causes of delay were denial (ratio of means (ROM) 4.36, p=0.002, 95% CIs 1.71-11.1), anxiety (3.36, 0.026, 1.16-9.76), non-recognition of symptoms (2.80, 0.004, 1.41-5.59) and smoking (1.76, 0.021, 1.09-2.86), respectively. These symptoms were associated with delay: finger swelling/discomfort (ROM=2.72, p=0.009, CIs 1.29-5.74), cough (2.53, <0.001, 1.52-4.19), weight loss (2.41, <0.001, 1.49-3.88), weakness (2.35, 0.001, 1.45-3.83), dyspnoea (2.30, 0.001, 1.40-3.80), voice change (1.90, 0.010, 1.17-3.10) and sputum (1.66, 0.039, 1.03-2.67), respectively, also having more than five symptoms (compared to 1-3) (3.69, <0.001, 2.05-6.64). No overall relation between within-patient delay and survival was seen. Conclusion: Using smoking registers, awareness literature and self-care manuals, primary care staff could liaise with ever-smokers regarding their symptoms, to ensure early referral to secondary care.