Oxygenation is an important component of the tumour microenvironment ,having a significant impact on the progression and management of cancer. Theoreticaldetermination of tissue oxygenation through simulations of the oxygen transportprocess is a powerful tool to characterise the spatial distribution of oxygenon the microscopic scale and its dynamics and to study its impact on theresponse to radiation. Accurate modelling of tumour oxygenation must take intoaccount important aspects that are specific to tumours, making the quantitativecharacterisation of oxygenation rather difficult. This review aims to discussthe important aspects of modelling tumour oxygenation, reoxygenation andimplications for treatment.