Cook told a congressional panel he was "proud of our contributions to the American economy" as he sought to deflect criticism stemming from a Senate investigation on shifting of profits offshore.
"We don't depend on tax gimmicks," Cook told a Senate Permanent Subcommittee on Investigations hearing. "We don't stash money on some Caribbean island.
He said Apple's international subsidiaries have "real operations with real products" and pay required taxes in the countries where they operate.
"The way I look at it is that Apple pays 30.5 per cent of its profits in taxes in the United States," he said.
"We do have a low tax rate outside the United States but this tax rate is for products we sell outside the United States."
Apple chief financial officer Peter Oppenheimer, also appearing at the hearing, said that while its Irish-based holding company pays little or no taxes, "the profits have already been taxed by foreign governments where the income is earned.