General haemotologists and laboratory scientists meet two types of problem when faced with blood disorders in children. The first is technical, and the second is due to the different spectrum of disease such patients present. This simple text has been written to help with both. It offers advice on protocols of investigation and methodology; on using techniques specific to paediatrics, and on where standard techniques have to be modified. There is a comprehensive list of reference to normal ranges, and also background clinical information on the various disorders which may be encountered - some of which will be familiar to the generalist, some of which may not.