COMMERCE, Calif. — Smart & Final Stores Inc. has introduced a new delivery platform powered by Instacart Inc. that sources groceries off the shelves of about 160 partner grocers and delivers the food to customers in more than 100 markets across the United States.

Last month’s announcement represents an expanded partnership between Smart & Final and Instacart, which first joined forces in 2015 to bring same-day delivery to Smart & Final’s customers. The warehouse-style store operator has since seen a 15-fold increase in sales through the platform.

“Smart & Final is doubling down on the partnership, giving customers the option to pair the club store’s everyday-low prices and farmer’s market freshness as experienced in-store with the added convenience of delivery straight to customers’ doorsteps,” the company said in a statement.

Smart & Final customers across Arizona, California and Nevada can now go to shop.smartandfinal.com to fill their virtual carts with produce, meat and club-size essentials, and have them delivered on the same day, often in as little as an hour, according to the ­statement.

“There’s no question that there is an increasing emphasis on online ordering and delivery in the grocery space, as today’s customer wants and deserves convenience,” explained Eleanor Hong, Smart & Final’s chief marketing and strategy officer. “Today, over half of our 253 Smart & Final stores offer delivery, both for household and business customers, and we continue to expand that reach as far as our partners at Instacart can offer it. We’re enthusiastic about delivery, and through our new e-commerce site, Powered by Instacart, we can give our online customers a platform to search, explore and order delivery directly from Smart & Final.”

Smart & Final was founded 145 years ago. It caters to households, restaurants and small businesses in six western states — Arizona, California, Nevada, Idaho, Oregon and Washington. The company also operates in northern Mexico.

Some members of San Francisco-based Instacart pay an annual fee of between $99 and $149 for unlimited deliveries of food and other merchandise from major retailers, including Publix Super Markets Inc., Wegmans Food Markets Inc., Costco Wholesale Corp. and Whole Foods Market.

“Part of Instacart’s mission to partner with the best retailers across the nation is the commitment to provide them with the best e-commerce experience,” said Nilam Ganenthiran, Insta­cart’s chief business officer. “We are thrilled to extend our partnership with a premier quality brand like Smart & Final and continue the success we are seeing with value grocers on the Insta­cart platform.”