All 22 local councils in Wales have reduced the amount of waste they send to landfill, according to a report by the Environment Agency in Wales.
Landfill allowances will reduce each year until 2010
New EU targets restrict the amount of biodegradable waste councils are allowed to bury.
Newport, Gwynedd and Monmouthshire councils all sent 30% less material to landfill sites than the allowed amount.
More than a million tonnes of waste is set to be sent to landfill in Wales in 2005-2006 but the targets will reduce.
By the end of the decade, councils in Wales will be expected to dispose of no more than 710,000 tonnes of biodegradable waste in landfill sites.
The results follow the first year of the new targets operating in Wales, which are designed to reduce greenhouse gas emissions from landfill.
Newport 32% less than target
Neath/Port Talbot 8%
% difference between waste landfilled and landfill allowances, 2004-2005
It is set against a background of concern that Wales is running out of landfill space, with the National Audit Office (NAO) Wales last year recommending that 500 new waste management facilities were needed by 2010.
The problem is most acute in the south west, with Swansea looking to send waste outside the city.
Results varied with Newport council sending 15,882 tonnes of biodegradable waste to landfill in the six months to March 2005, nearly two thirds of its allowance.
In Bridgend, where the allowance was 20,464 tonnes of waste, the council sent 20,301 tonnes to landfill sites.
Dr Helen Phillips, Director Environment Agency Wales admitted that the targets local councils faced in future years were "increasingly challenging".
Richard Parry Hughes, of the Welsh Local Government Association, said the figures demonstrated councils' ability and commitment to meet the targets.
"We too recognize that there is still a major step change in performance that is needed to meet our recycling, composting and landfill diversion targets," he added.