The carmaker showed off the new versions at an event on the eve of press days at the Los Angeles Auto Show.
The hybrid, powered by a 2.5-liter four-cylinder gasoline engine as well as an electric motor, initially will be sold in eight US states starting in January. The full-sized car will get 65 km's per gallon of gasoline in the city and 58km's on the highway, the company said.
It is Nissan's first hybrid powered car, company officials said.
Nissan has capacity to build 50 000 of the hybrids annually, but expects to sell 25 000 to 30 000 per year in 2007, the company said.
It will be sold in California, Massachusetts, New York, New Jersey, Vermont, New Hampshire, Connecticut and Pennsylvania.
"We think those markets are a good place to start," said Bill Bosley, vice president of the Nissan Division in North America.
The Altima will establish Nissan in the hybrid market, and the company is looking into spreading its hybrid technology to models in its lineup, Bosley said.
Nissan also unveiled a sleek coupe version of the Altima and a 200-horsepower sportier version of its Sentra small car called the SE-R. Versions of the Altima and Sentra went on sale this fall.
And the company gave a sneak peak at two models that will be officially unveiled at the North American International Auto Show in Detroit in January, the Rogue small car-based crossover vehicle and the Bevel, a crossover that resembles a small but sleek panel truck.