121 children under the age of 16 were hospitalised with anorexia last year.
New figures, released 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 bulemia.
237 were admitted with anorexia - and 94 per cent 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.
"It can cause serious physical and psychological harm to the sufferer," says Dr Martin Daly who is a former President of the Irish Medical Organisation.
"Eating disorders are one of the biggest challenges to our medical system at this time. At any given time, an estimated one in seven women is struggling with an eating disorder.
"A number of studies have found that up to a third of adolescent - one out of every three - believe they are over-weight, and up to 60 percent - two-thirds - are trying to lose weight."
There were just 10 admissions with bulimia last year.
The HSE says anorexia has the highest death rate of all mental health disorders.