A team of 14-year-olds, recruited by Herefordshire Council, found one in six shops were prepared to sell them cigarettes.
The group visited 47 shops in the county during one month and youngsters from the team were allowed to buy cigarettes in eight of them.
Three retailers have been already been prosecuted in the area this month for selling cigarettes to children.
Trading Standards Officers in Herefordshire are urging shop workers to always ask for identification when selling cigarettes to teenagers.
Disappointing results
Mike Pigrem, Herefordshire Council's Acting Trading Standards Manager, said the results were disappointing.
"Any such illegal sales will not be tolerated by Trading Standards.
"We therefore advise retailers not to sell to any young person unless they have a valid means to prove their age."
The owners of two shops in Hereford and one in Ross-on-Wye were fined by Hereford Magistrates Court for selling cigarettes to children under the age of 16-years-old.