By MIKE RAMSEY

Honda Motor Co. is hoping to jump-start sales of its Odyssey, the top-selling minivan in the U.S., with a sleeker design that it describes as "athletic," while adding space and better fuel efficiency.

Later this year, the auto maker will launch a redesigned version of the Odyssey that is sculpted and shaped to tone down the traditional squarish look and soccer-mom image—factors that have caused many consumers to stop buying minivans and move to sport-utility vehicles for hauling kids and cargo.

Honda, which has steadily increased its U.S. market share for more than a decade, needs a shot in the arm. Honda has an aging lineup with some of its best-selling models, including the Odyssey and Civic compact, facing stiff competition. In the first four months of the year, it has gained little ground even though its biggest rival, Toyota Motor Corp., has been hindered by recall and quality troubles. From January to April, Honda's U.S. sales rose 11.5%, while total light vehicle sales jumped 16.7%. During the same period, Ford Motor Co. and Nissan Motor Co. saw sales rise more than 30%. As a result, Honda's market share has slipped to 10.5% from 11% in 2009 through that period.

John Mendel, vice president of sales for Honda's U.S. unit, said the company doesn't try to "chase share." Mr. Mendel added that the dip in market share this year comes after strong sales in 2009, when nervous buyers flocked to Honda, while the economy slumped and General Motors Co. and Chrysler Group LLC sought bankruptcy protection. Honda's market share is now settling to a more normal level as the economy improves, he says.

The company is counting on the 2011 Odyssey to win over what it calls "hesitaters"—people who need the space and seating capacity of a minivan but don't like the idea of cruising around in a big box on wheels. Customer research found that people fall into three categories, said Vicki Poponi, a Honda product planning specialist in a presentation to journalists in Chicago a few months ago: "Those who embrace the minivan; those who outright reject it; and those who appreciate its practical value but remain somewhat on the fence due mainly to styling and image concerns."

More than in past years, Honda brought in customers to help them redesign the vehicle. Owners wanted to take away the boxy look and give it better handling and a sportier feel. A common desire by customers and Honda engineers was for a car that would be recognizable from 100 yards in a parking lot, said Christina Ra, a Honda spokeswoman.

To give the new Odyssey a sleeker profile, Honda gave the vehicle a more slanted windshield and a slightly tapered rear roof line. The rear-side window is angled to streamline the back end, and is also taller than the other side windows, creating a lightning-bolt-shaped line above the side panels. The Odyssey also will be wider and lower to the ground and have bumped out wheel wells, making it look more like a sport-utility vehicle. The new version will have a six-speed automatic transmission rather than a five-speed, and technology that can shut off three of its engine's six cylinders to reduce fuel consumption. This minivan, which will get 28 miles per gallon on the highway, is aimed at Gen-Y buyers, who are around 33 years old. The previous van was more suited to older couples, even grandparents who are part of the Baby Boomer generation, Ms. Ra said.

The Odyssey has the potential to be a big seller for Honda. It is the company's fourth best-selling model in the U.S., after the Accord sedan, Civic compact and CR-V crossover. But Honda faces an uphill battle with hesitaters. In Ann Arbor, Mich., Tammy McCollough, a mother of two hockey-playing boys, has been shopping for a replacement for her 2001 Odyssey, and she wants something more fashionable. "No one ever checks you out when you're driving a minivan," she said with a laugh.

The minivan segment has been steadily shrinking. Auto makers sold 424,007 minivans last year, down from more than a million in 2005, according to Autodata Corp. In 2000, total minivan sales hit 1.4 million vehicles. Minivans made up just 4.1% of the U.S. market in 2009, compared with 7.9% in 2000. Both GM and Ford have stopped making minivans and now offer seven-passenger crossovers like the Chevrolet Traverse and Ford Flex as family-movers.

The Odyssey will face competition from Toyota, which just updated its van, the Sienna, and Chrysler, maker of the Chrysler Town & Country and Dodge Caravan. This year, the Town & Country has outsold the Odyssey through April.