Ford's CO2 emissions have improved more than any other manufacturer, according to green car website Clean Green Cars.
The introduction the Ka and Fiesta, Ford's newest fuel-efficient models, are largely responsible for the reduction in CO2 emissions.
The Fiesta Econetic is also one of the greenest family cars on UK roads, emitting just 98g/km CO2 - making it exempt from road tax - and capable of achieving over 70mpg. The Fiesta Econetic is available priced from £13,495.
The lowest emitting Ford Ka, meanwhile, has a CO2 output of 112g/km.
Ford has improved overall emissions by an average of 9.6g/km of CO2, which translates into over 10,000 fewer tonnes of CO2 per year from the new Fords sold in the first three months of 2009.
Jay Nagley, publisher of Clean Green Cars, said: "New car carbon dioxide emissions are falling at an unprecedented rate and Ford is more than playing its part. Until last year, car CO2 output had been falling at less than 2% a year. Now real gains are being made with advanced technology, as demonstrated by Ford's Econetic range, offering ground-breaking levels of fuel economy and CO2."