Anorexia nervosa (AN) is associated with multiple medical complications. One of the rare permanent complications of AN is the deleterious effect that it has on a patient's bone mineral density (BMD). We report on the Dual-Energy X-ray Absorptiometry (DXA) findings of 336 consecutive patients with AN. Also, we investigated the effects of different factors on these DXA results. These factors included age, body mass index (BMI), percentage of ideal body weight (IBW), duration of illness, duration of amenorrhea, medications such as proton pump inhibitors (PPI) or selective serotonin reuptake inhibitors (SSRI), tobacco use and 25-hydroxy vitamin D levels. This study demonstrated a concerning high prevalence of reduced bone mineral density in patients with AN. Thus, the implication being that those involved in the care of patients with AN need to be cognizant of this serious complication and not be assuaged by the young age of this patient population.