Dyspnoea or breathlessness is a problem commonly encountered in the palliative care of many patients with advanced cancer, although its impact on the patient is frequently under-estimated. In advanced cancer, the aim of effective management is to minimize the patient's perception of breathlessness which, in turn, depends on reliable assessment. Most of the knowledge and experience of dyspnoea has been acquired through working with patients with chronic pulmonary disease and there is a dearth of literature relating specifically to the assessment of dyspnoea in advanced cancer, A critical analysis of available literature was undertaken and measurement instruments available for assessing breathlessness and their application to dyspnoeic patients with advanced cancer were reviewed, Dyspnoea is a complex, multidimensional sensation and its subjectivity makes it difficult to quantify, For patients with advanced cancer, dyspnoea may be one of many symptoms and measurement instruments need to take this into account, No single measurement instrument takes into account the different components of dyspnoea and as the final choice will depend on the purpose of assessment, it is likely that more than one instrument will be required.