Considerable progress has been made over the last two decades in delineating the key molecular events regulating the haemostatic function of platelets. Much of this new insight has been derived from the study of mouse models, in which the expression or structure of one or more platelet proteins has been genetically altered. Despite these advances on the research front, clinical progress in diagnosing patients with unexplained surgical bleeding or recurrent haemorrhage from mucocutaneous sites has been comparatively limited. There is a dearth of literature available to help physicians integrate and apply the burgeoning knowledge on platelet biology to diagnosing patients with atypical or unexplained platelet dysfunction. The purpose of this review is to summarise the major primary platelet disorders relevant to pathological bleeding in humans (excluding those primarily due to thrombocytopenia or acquired functional disorders), with a focus on lesions identified in mouse models that could represent candidate molecules for study in patients with impaired platelet function.