Platelet transfusions are used in clinical practice to prevent and treat haemorrhage in thrombocytopenic patients or patients with severe platelet dysfunction. In the UK, and abroad there has been a recent rise in platelet component demand. The three largest patient groups that use platelet components are patients with haematological malignancies (up to 67%), patients receiving cardiac surgery (up to 10%) and patients receiving intensive care (up to 8%). This review has explored some of the factors that may explain this recent trend within these three main groups. These factors include a rise in the general population, an ageing population, an increase in the incidence and prevalence of haematological malignancies, and changes in the management of patients with haematological malignancies. However, the only data available that can be correlated directly with national component data are the size of the total population. There is no evidence to support the premise that use of platelet components in patients receiving cardiac surgery or intensive care treatment is rising over and above the general rise in the population, but the data are sparse.