Background: For many patients going through diagnostic testing for cancer, the time from suspicion to diagnosis or rule-out, can be a confusing and anxious time. In 2007, Cancer Care Ontario began investing in the implementation of diagnostic assessment programs (DAPs) across Ontario, Canada to improve the quality of care during the diagnostic phase of lung cancer. DAPs consist of multidisciplinary healthcare teams that manage and coordinate a patient’s diagnostic care from testing to a definitive diagnosis. The objectives of the DAPs are to: 1) decrease time from suspicion to diagnosis or resolution; 2) optimize the patient’s experience during the diagnostic process; 3) optimize satisfaction and experience among primary care providers and specialists; and 4) provide a sustainable solution by offering good value for money. Today over 35,000 patients have been diagnosed in one of the 18 lung DAPs that exist across the province. Methods: The implementation of DAPs featured the introduction of a patient navigator to act as the primary point of contact for patients, improve the patient experience and ensure their patients were progressing through any required diagnostic imaging and consultations in a timely manner. Cancer Care Ontario also engaged with primary care providers to refer patients with findings suspicious for lung cancer to DAPs as early as possible to ensure they benefited from organized assessment. Cancer Care Ontario has collected patient level data to measure wait times and implemented a patient survey to assess patient experience. Results: In the past five years, the median wait time from referral to a lung DAP to diagnosis or rule out has decreased by 19% to 24 days and the 90th %tile has decreased by 28% to 51 days. The large majority of patients have had a positive experience with their DAPs, with 95% of patients scoring their experience in the diagnostic process as “good” or “excellent”. Conclusions: The implementation of DAPs across the province is seen as a valuable component of quality of care by improving the diagnostic phase of cancer. The sustainability of the DAP model is demonstrated by the continued improvements in access and maintained patient experience in spite of growing volumes (91% increase in the past five years).