To evaluate menorrhagia in a cohort of women with glycogen storage disease type I because it appears to be an under-recognized problem in females of reproductive age.A retrospective chart review was performed on 13 menstruating patients with glycogen storage disease type I (age 23-48 years) for a diagnosis of menorrhagia.Nine (69%) (confidence interval 0.39-0.91) women had development of menorrhagia. Median hemoglobin values in these patients were generally low (range 9.5-12.85 g/dL) but not different from those of the nonmenorrhagia group (hemoglobin range 9.55-11.0 g/dL) with glycogen storage disease type I. Four patients with menorrhagia required hospitalization or emergency department visits for treatment of menorrhagia. Two of the four patients hospitalized required blood transfusion, with an additional patient requiring a transfusion during pregnancy. Eight patients (89%) either were recommended to have or required medical or surgical treatment of their menorrhagia.Glycogen storage disease type I is associated with menorrhagia. The evaluation should include assessment of coagulation functions and referral to a gynecologist, hematologist, or both, because bleeding diathesis and polycystic ovary syndrome are common in patients with glycogen storage disease type I.