BackgroundCigarette smoking in people with cancer is associated with negative treatment related outcomes including increased treatment toxicity and complications, medication side effects, decreased performance status and morbidity. Evidence based smoking cessation care is not routinely provided to patients with cancer. The purpose of this study is to determine the effectiveness of a smoking cessation implementation intervention on abstinence from smoking in people diagnosed with cancer.MethodsA stepped wedge cluster randomized design will be used. All sites begin in the control condition providing treatment as usual. In a randomly generated order, sites will move to the intervention condition. Based on the Theoretical Domains Framework, implementation of Care to Quit will include i) building the capability and motivation of a critical mass of key clinical staff and identifying champions; and ii) identifying and implementing cessation care models/pathways. 2160 patients with cancer (diagnosed in the prior six months), aged 18+, who report recent combustible tobacco use (past 90 days or in the 30 days prior to cancer diagnosis) and are accessing anti-cancer therapy, will be recruited at nine sites. Assessments will be conducted at baseline and 7-month follow-up. The primary outcome will be 6-month abstinence from smoking. Secondary outcomes include biochemical verification of abstinence from smoking, duration of quit attempts, tobacco consumption, nicotine dependence, variables, provision and receipt of smoking cessation care, mental health and quality of life and cost effectiveness of the intervention. DiscussionThis study will implement best practice smoking cessation care in cancer centres and has the potential for wide dissemination. Trial registrationThe trial is registered with ANZCTR (www.anzctr.org.au): ACTRN (submitted, awaiting approval due to ANZCTR delays) prior to the accrual of the first participant and will be updated regularly as per registry guidelines.