The army is targeting schools in some of the poorest areas of Wales to find new recruits, Plaid Cymru has claimed.
Plaid Cymru obtained figures under the Freedom of Information Act
It said figures show regional variations in recruitment officers' visits and has asked the Welsh Assembly Government to ban them from schools.
The Ministry of Defence (MoD) said Army visits were by invitation only and were not to recruit but to raise awareness.
The assembly government said it was up to each school to decide on career opportunities offered.
Plaid said it had used the Freedom of Information Act to obtain figures on visits from the Army Recruitment Division for 2005-06.
The party said the figures showed that schools in the most deprived areas were visited 50% more often than those in affluent areas and that there were big regional variations.
Schoolchildren in Swansea were visited more than 10 times on average during that period while children in the Vale of Glamorgan had no visits at all.
The MoD said the status of the school was "not an issue" and the same opportunities were offered to all.
Plaid AM Leanne Wood is writing to Welsh Education Minister Jane Davidson asking for a ban on army recruitment in schools.
"The army is clearly targeting the most deprived areas in Wales," she said.
"I believe that young people in Wales should not be subjected to armed forces propaganda.
"If pupils want to join the army they can visit any number of recruitment centres around Wales."
A MoD spokesman said the Army visited schools "on specific invitation only".
The army has recruitment offices in many town and city centres
He said: "The status of a school is not an issue - the same opportunities are offered to all.
"The Army does not recruit in schools, but seeks to raise awareness of the Army and its place in a democratic society while building interest in the Army and its careers."
An assembly government spokesperson said it was "up to individual schools to take decisions on career opportunities for their pupils and how those opportunities are offered".
Anna Brychan, director of the National Association of Head Teachers (NAHT) Cymru, said careers in the armed forces were one of many choices put before children.
She added: "I can understand why these figures might cause concern if it appears that members of the armed forces are disproportionately coming from some backgrounds, especially given the content of the daily news at the moment.
"But ultimately what head teachers are doing is giving pupils the widest possible range of career options backed up by specialist advice from school staff.
"That, I think, is the best way of giving our youngsters the best range of choices possible."