Menorrhagia at the time of menarche is relatively common and historically attributed primarily to immaturity of the pituitary-ovarian-uterine axis. Intuitively, a proportion of these patients should have an underlying disorder of haemostasis, given the 5-20% prevalence of von WillebrandÕs disease and the ‡20% prevalence of platelet dysfunction in light of recent epidemiological studies in menorrhagia, although the average age of the patients in those studies has been 35 years. However, there are a few comprehensive studies in the adolescent population determining whether widespread haemostasis evaluation should be carried out in adolescents presenting with menorrhagia. A retrospective chart review study of disorders of haemostasis was carried out in 61 consecutive adolescent patients, ages 11-19 at the time of evaluation referred to the Hemophilia Treatment Center (HTC)/Hematology unit. The mean and median ages were 15 ± 2.2 and 14 years (11, 19), respectively. Standard evaluation included complete blood count, prothrombin time, partial thromboplastin time, von Willebrand factor (VWF) levels and platelet aggregation. The proportion of patients with VWF deficiency was 22/61 (36%) [95% confidence interval (CI), 24-49%]; the proportion of patients with platelet aggregation abnormalities was 4/61 (7%) (95% CI, 2-16%). There was no difference in the frequency of additional muco-cutaneous bleeding symptoms. A relatively high proportion of adolescents are identified with an underlying disorder of haemostasis when referred to an HTC for evaluation of menorrhagia. This involves in part a selective referral bias, but underscores the role of the HTC in evaluating adolescents referred with menorrhagia for an underlying bleeding disorder, given the relatively high yield of haemostatic disorders detected in this setting.