BACKGROUND: Previous studies have focused on the treatment received by rural cancer patients and have not examined their diagnostic pathways as reasons for poorer outcomes in rural Australia. OBJECTIVES: To compare and explore diagnostic pathways and diagnostic intervals in patients with breast, lung, prostate or colorectal cancer from rural Western Australia (WA) to inform future interventions aimed at reducing time to cancer diagnosis. METHODS: Mixed methods study of people recently diagnosed with breast, lung, prostate or colorectal cancer from the Goldfields and Great Southern Regions of WA. Qualitative interviews explored participants' diagnostic pathways and factors underlying differences observed between individuals and cancers. Data were extracted from general practice and hospital records to calculate intervals from first presentation in general practice to final diagnosis. RESULTS: Sixty-six participants were recruited (43 Goldfields and 23 Great Southern region; 24 breast, 20 colorectal, 14 prostate and 8 lung cancers). There were significant overall differences between cancers in time from presentation in general practice to referral (P = 0.045), from referral to seeing a specialist (P = 0.010) and from specialist appointment to cancer diagnosis (P ≤ 0.001). These differences were due to the nature of presenting symptoms, access to diagnostic tests and multiple visits to specialists. Breast cancer was diagnosed more quickly because its symptoms are more specific and due to better access to diagnostic tests and specialist one-stop clinics. CONCLUSIONS: Interventions to improve cancer diagnosis in rural Australia should focus on better case selection in general practice and better access to diagnostic tests, especially for prostate and colorectal cancers.