OBJECTIVES: With an absence of recent healthcare resource utilisation estimates associated with disease progression through CML phases, a clinical expert survey aimed to obtain up-to-date estimates for England and Wales for chronic (CP), accelerated (AP) and blast phases (BP) of CML. METHODS: A semi-structured interview was conducted with 12 consultant haematologists based in hospitals in England (10 clinicians) and Wales (2 clinicians). Clinician selection ensured a cross-section of hospital type and geographical location. The questionnaire was designed to capture all CML phases, and CP by complete cytogenetic response (CCyR) or no CCyR. The survey covered: outpatient visits, tests/investigations, procedures, hospital inpatient use, end of life (EoL) care. Analysis consisted of mean estimates per three months for CP, and per one month for AP/BP. Frequency tables captured absolute resource use within phases.  RESULTS: Clinical experts represented a range of hospitals (6 Teaching, 3 Centre of Excellence, 3 General Hospitals). Overall, mean resource utilisation increased with disease progression. Hospital inpatient (general and ICU) days were estimated to be zero (CP), mean of 0.71 days (AP) and 8.88 days (BP) per month. Estimated mean nurse or haematologist led outpatient visits were 1.22 (CCyR) or 2.1 (no CCyR) per 3 months, 1.38 (AP) and 3.45 (BP) per month. Use of diagnostic tests/investigations increased across phases, although mutational analysis testing appears rarely performed despite guidelines stating use in case of treatment failure. Blood or platelet transfusions were only used in AP and BP and were significantly higher in BP. EoL care was estimated as 51.45% in hospital, 23.09% hospice and 25.45% other e.g. home. CONCLUSIONS: CML treatment aims to maintain patients in CP. Resource utilisation is lowest in CP, increasing with disease progression. Estimates can be used in UK economic models of CML treatments for HTA submissions and as a basis for further data collection on CML resource use.