Background: AML is one of the most common and acute diseases among the types of leukaemia. The treatment costs for AML/APML are considerably high as it involves the use of expensive treatments (such as stem cell transplantation). Over the past 20 years, the topic has attracted the interest of an increasing number of economic evaluation researchers, with the goal of reducing the related costs without compromising the quality of care and the clinical outcomes. However, no relevant overall/lifetime treatment cost study has been carried out yet, mainly due to UK data availability constraints. Taking the above into consideration, the aim of the study was to calculate the overall/lifetime treatment costs by applying the bottom-up method. Methods: In order to obtain overall/lifetime cost for AML/APML treatments, an innovative three-phase costing study was conducted on 239 newly diagnosed (during September 2004 to September 2006) adult AML/APML patients in Haematological Malignancy Research Network (HMRN). The study employed the bottom-up costing method and the retrospective treatment pathway. The involved patients were followed from diagnosis date onwards, until death or cure. Treatment pathways, and all the relevant clinical information (including treatments, tests, and duration) were extracted from patients’ medical notes on a regular basis by well trained research nurses. Unit costs were determined from various sources, including the British National Formulary and the unit costs of health and social care from the Personal Social Services Research Unit (PSSRU). Finally, an exploratory analysis was carried out on the obtained cost results in order to uncover potential cost predictors. Results: The average overall treatment cost per patient was found to be £27290. This cost was mainly the result of the first-line treatment cost and the number of AML recurrences. The major cost driver throughout all disease phases was hospitalization, followed by drug and complication treatment. Age, death or not, number of treatments, type of primary induction treatment, and response to induction treatment were found to be highly associated with overall treatment costs. Conclusion: The results of the current study showed that the lifetime/overall costs of AML/APML treatments was considerably high (although variance between patients was high as well), and uncovered the potential existence of a number of cost predictors. It is expected that these findings could help to bridge the gap between the actual cost and the NHS reference costs, while the potential cost predictors could assist decision makers in relation to health policy or clinical guideline issues.