Mother's Day is a big day for moms. But it's also the biggest day of the year for the restaurant industry.

More than a third of the nation's moms dine out on the second Sunday in May, according to the National Restaurant Association. Thousands of customers visit a restaurant at least twice on that day.

“Over the years, when the association surveys consumers for the top days for dining out, Mother's Day hands down comes at the top," says Hudson Riehle, the NRA's head of research. "That has remained unchanged for as long as we've done holiday research.”

It's become traditional for families to have at least one meal at a restaurant on Mother's Day, explains Brandon O'Dell, owner of O'Dell Restaurant Consulting in Kansas City, Missouri. Eating out is a way to treat moms while not making life too tough on dads.

"Moms aren't expected to prepare the meals, and the father and kids aren't always capable of making the meal," he says. "So, they go out."

As a result, most restaurants cater to families' many tastes on Mother's Day, whether it's a buffet, prix fixe special or the regular menu. Some operators give moms a free rose or dessert, and a few even throw in a complementary cocktail—if it's legal to do so.

Prices for prix fixe offerings range from about $25 per head to more than $100 at several Beverly Hills, California, locations.

While many eateries focus on brunch for Mother's Day, NRA statistics reveal the most popular time to dine out on the day is dinner—59 percent of people opt to dine out then. Brunch/lunch is at 51 percent.

However, a survey last year by OpenTable determined that noon is the most popular time for Mother's Day reservations.

The San Francisco company, which provides free online reservations at more than 12,000 restaurants, also found that moms usually get to choose the time to dine.

Buffets have become a staple of Mother's Day because they're a treat for diners and may be easier for operators.

"Restaurants can be so busy that day that it would be a nightmare in the kitchen to cook too many different menu items," says Bonnie Riggs, restaurant industry analyst for consulting firm The NPD Group. "So you see a buffet or more of a fixed-price menu."

All types of dining spots feature a Mother's Day buffet. These include hotels and country clubs that regularly offer Sunday buffets, as well as full-service restaurants that don't often have a buffet.

Cabernet Steakhouse in suburban Atlanta is open only two Sundays, and Mother's Day is one of them. The reason is simple.

"It's Mother's Day," says general manager Jason Zaleski. The restaurant has been open that day for all of its 11 years because it makes financial sense.

Cabernet has a buffet brunch and a prix fixe dinner, along with its steakhouse classics.

The buffet features prime rib, lobster tail, smoked salmon mousse and oyster on the half shell, along with typical breakfast items. The cost is $49.95 for adults, $19.95 for kids.

At Maggiano's Little Italy, individual operators can opt to have a Mother's Day buffet, said Danielle Smith, spokeswoman for Brinker International, parent of the 44-unit chain.

Maggiano's Nashville restaurant will be open from 9:30 a.m. to 2 p.m., featuring breakfast items (French toast, bacon, sausage, eggs), salads, Italian items (ravioli and ziti), a carving station with ham and pork, and various desserts.

The price is $32.95 for adults and $15.95 for children.

Michael's in Santa Monica, California, offers a popular brunch.

Known for its elegant meals and beautiful outdoor/indoor seating, the restaurant is usually closed for regular business on Sundays, although it often hosts parties then.

Owner Michael McCarty has offered a Mother's Day brunch for 32 years. More than 200 customers dine there that day.

"We have a great menu, a classic menu, and it's a lot of fun," says the French-trained owner, who helped popularize California cuisine.

The brunch has both sophisticated and kid-friendly dishes. They range from eggs Benedict and oysters to blueberry pancakes and pastries. Along with the three-course prix fixe menu, Michael's serves various cocktails and a popular blood orange mimosa.

"Mother's Day has really been a tradition here," McCarty says. "We have second and third generation customers that day. And I'd say there is at least one mom at every table."

Some upscale chains make a big deal of Mother's Day. The Brio units of the upscale Bravo/Brio Restaurant Group open earlier than usual for breakfast/brunch, and they have lunch and dinner menus, too. The Bravo! units serve lunch and dinner.

What’s served depends on where the restaurant is located, says Saed Mohseni, CEO of the Columbus, Ohio-based company. The 38 Brio restaurants, for instance, are in regional retail centers, where customers are looking for an experience. The 47 Bravo! eateries are freestanding with a more traditional ambiance.

"Mother's Day is important to us," Mohseni says. "We know what our customers want, and we tailor our menus to fit their needs."

Most experts believe Mother's Day will be busier this year because of the improved economy. A recent NPD Group survey found that fine dining and hotel restaurants had a strong eight percent increase in traffic during the three months ending in February.

"We will spend more, too," Riggs predicts.

Still, value remains critical, and a number of restaurants are offering special deals, such as free food or drinks to moms. A few are providing gift cards.

OSI Restaurant Partners' Fleming's Prime Steakhouse & Wine Bar is giving moms dining there on Mother's Day a $25 dining card for a future visit. The company's Roy's Hawaiian Fusion Cuisine is handing a $20 bonus card to moms visiting that entire weekend.

"It's no surprise there are a host of different promotional activities," says the NRA's Riehle. "It's an important day—one that can help restaurant operators build strong relationships and good will with customers."

By Barney Wolf