Citibank has partnered with mobile payment enabler Obopay to let checking account customers try out a bank-linked mobile person-to-person payment service this summer.

The service will allow Citibank customers to receive and send money from their mobile phone directly into or out of their checking account. New and existing Citibank customers will be able to enroll in the Citi Obopay mobile payment service in a highly secure manner through the site at http://www.citibank.com or at branches in select markets.

"We believe that although it is a nascent market for mobile services, consumers will quickly find the utility in exchanging funds while they are on the go," said Michael Garelik, vice president of growth, ventures and innovation at Citi, New York. "It is really extending the checking account to new heights and adding flexibility that never extended to social payments."

Citibank trial participants will be able to add the Obopay functionality to their existing checking accounts. Then, using the service's mobile application, their mobile Web browser or text messaging, Citibank customers can send or receive money from others with the service directly from their mobile phones.

Citi introduced Obopay to select Citi customers last year during a limited consumer trial in Chicago and Boston.

Response to this trial confirmed that consumers are eager to use services that directly address their changing lifestyle needs and give them fast and convenient access to funds through their mobile phones.

"Adding Obopay's mobile functionality to Citi checking accounts is a step towards the future of financial services," said Ramy Mora, vice president of marketing for Obopay. "The on-the-go lifestyle of today's consumer has created the demand for instant and convenient money transfer."

Citibank is not the first financial institution to let customers rely on their phones for banking.

For example, Chase lets customers text their account to get their balance, recent transactions and statements via SMS. Bank of America, too, offers similar functionality to its 1 million mobile banking customers.

"We have been consumer-focused in our approach to this service," Mr. Garelick said.

"Customers have told us that they would be interested in being able to send money in real time," he said. "As always, consumers will define their specific uses for the service and learning from them is our most important goal."

The Citi Obopay mobile payment service is designed around customers' lifestyle.

For example, parents can instantly send money to children away at college.

Also, friends can reimburse one another using this service as well, without ever exchanging money.

"Many of these social money transactions now are quite cumbersome," he said. "A person hands cash that he owes to a friend. The friend only has $20 bills and she can't make change. So no one leaves happy.

"Others do this by a check that they then send in the mail or needs time to clear," he said. "The Citi Obopay service will be faster and more convenient than either of these situations, and provide a record for how much you sent, to whom, and when. Plus you can still access the funds as you would normally with your Citibank Debit card."