National Car Rental is launching its eighth annual "One-Two-Free" Emerald Club promotion, which runs through Jan. 31, 2011.

For every two qualifying rentals of two or more days with National, Emerald Club members earn one free rental day - with no limit to the number of free days earned. Participating members can also earn a free rental day for referring a friend in addition to their standard program rewards for all rentals. Emerald Club customers must register at www.emeraldclubpromos.com/12Free to be eligible.

This year's program allows Emerald Club members to redeem their free rental days from Sept. 3, 2010, to June 25, 2011. Free days can be used anytime, up to three at-a-time, including weekends. In keeping with the speed and convenience of the Emerald Club rental experience, National notifies participants about their free rental days via e-mail.

There are no enrollment fees to join National's Emerald Club, which offers faster service at airports, free upgrades and a choice of program rewards. "The priority is to ensure our loyal customers receive the best value incentives and customer service programs available in the car rental industry," said Rob Connors, assistant vice president for the National Car Rental brand. 

"Our eighth 'One-Two-Free' Emerald Club promotion is an opportunity to once again thank our members for their business with National Car Rental," Connors said.

The Emerald Club received the SmarterTravel Editors Choice Award in 2010 for "Best Rental Car Loyalty Program," and earned the National Business Travel Association's 2010 Innovative Award for Travel Convenience and Efficiency.