It made an additional provision of 135 million pounds to compensate customers who bought payment protection insurance that they did not need, raising the total provision for insurance mis-selling to 1.3 billion pounds.
The loss for the three months ending June 30 was down from a loss of 897 million pounds a year earlier. Operating profit fell 22 percent to 650 million pounds, and revenue fell 5.4 percent to 6.4 billion pounds.
"Expectations for RBS are generally pretty low, and they didn't disappoint," Gary Greenwood, an analyst at Shore Capital in Liverpool, told Bloomberg News. "With RBS it's all about the health of the balance sheet and they're making excellent progress in those terms."
RBS said it had dismissed a number of employees for misconduct as a result of investigations into the fixing of the London interbank offered rate (LIBOR), a key market index.
Chief executive officer Stephen Hester said the issue remained under investigation. So far, only Barclays has been fined for its part in the scandal.
"This is a really important reputational issue for the industry," Hester said. "It's one that we must all take with all seriousness."
Hester again apologized for the computer problems, which struck on June 16. Many customers complained that their deposits had not been posted promptly, leaving their accounts unable to pay bills. Hester has said he would not accept a bonus for this year because of the issue.
The worst problems were in RBS' Ulster Bank subsidiary in Northern Ireland, where Hester said problems with customer accounts had "now been largely rectified."