The ruling coalition, with support from the opposition Democratic Left Alliance, has overturned a presidential veto against lowering the compulsory age which children begin school.
Children will now start their school career at six years old – a year younger than has been the case to date.
President Lech Kaczynski had vetoed the plan earlier this month, arguing that an extra year full of children at school would put an intolerable strain on the education budget.
But Education Minister Katarzyna Hall has promised extra funds would be available, with some of the shortfall being made up by the EU.
Parents can choose to start sending their six year olds to school as of this September, though it will be compulsory from 2012.
To overturn a presidential veto, three fifths of MPs must vote against it. (pg)