Despite complaints that banks and credit card companies are gouging customers by charging outrageous interest rates, the Senate on Wednesday turned back an effort to cap interest rates at 15 percent.

The proposal by Senator Bernard Sanders, the Vermont independent, drew only 33 votes and needed 60. A bipartisan group of 60 senators opposed it, though the Senate pushed ahead with other restrictions on credit cards. Some Democrats and consumer groups have said that an interest cap is needed to put real teeth into an otherwise solid bill.

The bill still contains provisions that would prohibit companies from raising interest rates on existing balances unless a card holder was 60 days behind, and then would require the rate to be restored to its previous level if payments were on time for six months. Consumers would have to be notified of rate increases 45 days in advance. Companies would not be allowed to charge late fees if they were late in processing a payment.

Other backers of the measure calculated that an interest rate ceiling would doom the popular legislation. The banking industry, which had some heavyweight representatives monitoring the vote, warned that an interest rate limit could cause a sour reaction in the financial markets. But Mr. Sanders said the card companies and banks were engaged in conduct that could get others hauled into court. He said one-third of all credit card holders are paying interest above 20 percent and as high as 41 percent.