The business shortened its name to "the Lay's Company" in 1944 and became the first snack food manufacturer to purchase television commercials, with Bert Lahr as a celebrity spokesman. His signature line, "so crisp you can hear the freshness," became the chips' first slogan along with "de-Lay-sious!" As the popular commercials aired during the 1950s, Lay's went national in its marketing and was soon supplying product throughout the United States.
In 1961, the Frito Company founded by Elmer Doolin and Lay's merged to form Frito-Lay Inc., a snack food giant with combined sales of over $127 million annually, the largest of any manufacturer. Shortly thereafter, Lays introduced its best-known slogan "betcha you can't eat just one." Sales of the chips became international, with marketing assisted by a number of celebrity endorsers.
In 1965, Frito-Lay merged with the Pepsi Cola Company to form Pepsico, Inc. and a barbecue version of the chips appeared on grocery shelves. A new formulation of chip was introduced in 1991 that was crisper and kept fresher longer. Shortly thereafter, the company introduced the "Wavy Lays" products to grocer shelves. In the mid to late 1990s, Lay's modified its barbecue chips formula and rebranded it as "K.C. Masterpiece," named after a popular sauce, and introduced a lower calorie baked version and a variety that was completely fat-free (Lay's WOW chips containing the fat substitute olestra).
In the 2000s, kettle cooked brands appeared as did a processed version called Lay's Stax that was intended to compete with Pringles, and the company began introducing a variety of additional flavor variations.
Frito-Lay products presently control 55% of the United States salty foods marketplace.
In Argentina, Lays was comercialized before 2001 with the name Frenchitas and Chizitos for the Cheetos.
In Australia, Pepsico acquired the The Smith's Snackfood Company in 1998 and marketed Frito-Lay products under that label, using the name Thins. After Thin's was sold to Snack Brands Australia (Owned by Arnotts), Smith's produced a line of potato chips under the Lay's brand for a brief period of time. The Lay's line was eventually rebranded as Smith's Crisps, while the traditional Smith's line was renamed Smith's Crinkles. Thins is still sold in Australia as a direct competitor to Smith's Crisps.
In Canada, the chips are distributed through the Lay's label.
In Mexico, Pepsico acquired Sabritas S. de R.L. in 1966. Lay's along with other products such as Cheetos, Fritos, Doritos and Ruffles are marketed under the Sabritas brand. The logo for the Mexican company sports the red ribbon, but it has a stylized smiling face instead of the sun. It controls around 80% of the market there.
In Israel, the Lay's label is distributed with the name Tapochips (תפוצ'יפס)
In Germany, Lay's are sold in three varieties: Lay's, Lay's Light and Lay's Sensations (Thai Sweet Chili/Red Paprika/Oven Roasted Chicken and Thyne - [available in Cologne/Aachen only through the German locations of Delhaize). Lay's Super Chips (Heinz Ketchup/Mexican Pepper/Perfect Pickles/Salt 'n' Pepper [all through Delhaize) and Lay's Baked Chips (Mediterranean Herbs/through Delhaize). As with Doritos, Lay's are manufactured, distributed and imported in Germany by Frito Lay's Benelux division, Smith's Food Group. Several flavors as noted above are only available through Delhaize (Belgian supermarket chain)] which has opened 2 locations in Cologne and Aachen (Delhaize Germany locations, Lay's Flavors Benelux).
Except for barbecue-flavor potato chips, which were introduced no later than 1958, up until the last 20 years, the only flavor of potato chips had been the conventional one. Despite an explosion of new flavors, the unadorned original is still the selection of 81% of consumers. 
In the United States, Lay's offers a number of flavor combinations, in addition to the classic chips. Flavored products in the traditional fried varieties include sour cream & Onion, Barbecue, cheddar & sour cream, Hidden Valley Ranch, salt & vinegar, salt & pepper, Flamin' Hot, dill pickle, limón (Lime) and a thicker "Deli style" chip. Canadian sellers have a number of varied flavors, with curry, ketchup, poutine, pizza, Fries'n Gravy, roast chicken, smokey bacon, salsa, wasabi, spicy Indian masala and sea salt and pepper brands available. The marketing success of these flavors in Canada sometimes leads to a limited time offering of a flavor to the south, with the dill pickle recently appearing in the United States after a successful run.
Interestingly the name 'sour cream' has got Lay's into a lot of confusion in some countries. In India for instance the name was changed to style cream after consumers reported their discomfort with the idea of 'sour' cream
In the baked products, there are classic, barbecue and sour cream & onion varieties. The kettle cooked version includes original, sea salt & vinegar, mesquite barbecue and jalapeño brands. Wavy Lay's have original, hickory barbecue, ranch and au gratin flavors while Lay's Stax offers original, sour cream & onion, cheddar, barbecue, ranch, pizza and salt & vinegar. The newest variety, Lay's Natural has thick cut barbecue and sea salt brands.
The WOW! brand was rebranded in 2004 as Lay's Light after the olestra formula was altered and the U.S. Food and Drug Administration allowed removal of warnings about various health consequences of the fat substitute.
Outside North America, Lay's in Greece and Cyprus are made and packed by Tasty Foods and Corina Snacks LTD, with Mediterranean flavors which include Feta cheese flavor, Tzatziki flavor, Olive and Tomato, Oregano, Sea Salt & Black Pepper and various more. There are hundreds of sub-variations of the Mediterranean line and the company performs constant experimentations to create new flavors and adjust them to each country's liking. In some countries such as Argentina variations of the Mediterranean tastes exist include Olive Oil and Parmesan Cheese, Olive Oil and Tomato, Olive Oil and Basil, Greek Tzatziki Cheese with onions, Lasagna, Beef Carpaccio with Parmeggiano and Smoked Manchego Cheese. In Belgium there is a version of Cucumber and Goats Cheese. Finally in Chile there is a version of Lemon and Cilantro (Coriander) and Sour Cream and Onions.
In Australia, a cilantro version exists while a hot & sweet chili, sweet corn and cotija cheese brand can be found in South America.
Another flavor sold primarily in southern Asia is called "Magic Masala." This flavor is very popular in India, Pakistan, and Bangladesh. Flavors featured in Thailand include Nori Seaweed, Korean Bulgogi, Green Tea, Spicy Chili Squid, Seafood and Mayonaise, and Spicy Seafood.
There are a number of unique products in the United Kingdom sold under the Walkers label, including prawn cocktail, beef & onion, Greek kebab and Marmite yeast extract. Under the Smith's label in Australia, unique flavors include Greek Feta & Herb and Italian Tomato & Basil.
Russia has "Lay's MAX" chips (Chicken, Sour cream & Onion, Sour cream & Cheese, Ham & cheese flavors) and some international "Lay's" flavors plus Russian "Lay's" flavor - Mushrooms & Sour cream.
In parts of South America (notably Argentina and Uruguay), Lay's flavored products are sold with the "Lay's Mediterraneas" label, and include such flavors as ham, tomato and basil, tomato Parmesan, and oregano. Peru has "Lay's Sabores Peruanos" (Lay's Peruvian Flavors), with flavors like queso andino (Andean cheese); also recently was released Lay's Dips, that includes a "Peruvian Criollo Chili" sauce sachet.
In Ukraine there is crab, bacon, cheddar, and sour cream and green onion
There are currently 12 regular Lay's flavors in Canada, though there are more, available only in certain parts of the country. The flavors available nationwide are the following: Classic (yellow), BarBQ (black), Salt & Vinegar (teal), Ketchup (dark red), Wavy Original (red), Dill Pickle (bright green), Smokey Bacon (brown), Sea Salt & Pepper (silver), Sour Cream & Onion (green), Roast Chicken (light brown) and finally Lightly Salted (bright blue). Also, in select Canadian markets (Toronto & Vancouver) Lay's has introduced international flavors such as "Spicy Curry" and "Spicy Indian Masala" to appeal to a wider consumer group.
Lay's have entered the German market with some success in the last couple years. All 3 key Lay's brands are distributed with 2 flavors for each brand. The following flavors are marketed in Germany:
A one ounce (28 gram) serving of Lay's regular potato chips has 130 calories and contains ten grams of fat, with three grams of saturated fat. Kettle cooked brands have seven to eight grams of fat and one gram of saturated fat but are 140 calories. Lays Natural has nine grams of fat, two grams of saturated fat and 150 calories. Stax typically contain ten grams of fat, 2.5 grams saturated fat and are 160 calories per serving. Wavy Lays are identical to the regular brand except for a half-gram less of saturated fat in some combinations. The various brands do not contain any trans fats.
The baked variety, introduced in early 2004, feature 1.5 grams of fat per one ounce serving, and have no saturated fat. Each serving has 110 to 120 calories. Lay's Light servings are 75 calories per ounce and have no fat.
Lays Classic Potato chips were cooked in hydrogenated oil until 2007. Currently, the chips are made with 100% pure sunflower oil.
They have many flavors in the Baked Lays as well. Baked Lays are produced in cheddar, barbecue, sour cream and onion, and original.