Barbara Woodall, 34, of Bury, was put under curfew and ordered to attend parenting classes.
Magistrates were told that her two daughters each spent less than 15 of a possible 179 days at school between September 2004 and January this year.
Woodall pleaded guilty to two aggravated offences of knowingly allowing the girls' absences from the town's Broad Oak high.
She was convicted of truancy offences in April 2003 and January 2004. In the latest case an education welfare officer visited the family home 15 times but this had no impact on the girls' attendance.
london admissions board defends record, Letters 25