Some 121 children under the age of 16 were hospitalised with anorexia last year.
New figures, released to Newstalk under the Freedom of Information Act, show the condition affects far more girls than boys.
A total of 247 people had inpatient admissions in hospital last year, due to either anorexia or bulimia.
Some 237 were admitted with anorexia - and 94% of them were female.
A total of 121 boys and girls under 16 were hospitalised with this disorder - along with 77 aged between 16 and 24.
Dr Martin Daly is former president of the Irish Medical Organisation (IMO). He says anorexia is a devastating illness.
"It can cause serious physical and psychological harm to the sufferer.
"Eating disorders are one of the biggest challenges to our medical system at this time.
"At any given time, one out of every seven women is estimated to be struggling with an eating disorder.
"A number of studies have found that up to a third of adolescent girls - that means one out of every three - believe they're overweight.
"And up to 60%, two-thirds of them, are trying to lose weight".
There were just 10 admissions with bulimia last year.
The Health Service Executive (HSE) says anorexia has the highest death rate of all mental health disorders.
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