During the talks, Rice told Karzai that the United States will assist Afghanistan as long as such help is necessary.
Speaking at a news conference after the meeting, Rice praised Afghanistan's moves toward democracy.
"Afghanistan is now inspiring the world with its march toward democracy, with the successful presidential elections that brought you [Karzai], the first elected president of Afghanistan, and then the parliament that has just been elected," Rice said. "And in both cases we recognize that the foundation is being laid for a strong and democratic Afghanistan."
Karzai's government if fighting insurgents loyal to the Taliban regime, who were ousted in late 2001 by a U.S. invasion force and Afghan militias.
Karzai today told Rice that he believes the insurgents are receiving support from Afghanistan's booming drug trade.
Rice is on a three-day tour of South and Central Asia. She arrived in Kabul today, and is later expected to go to Pakistan.
Rice began her tour yesterday in Kyrgyzstan, and is also scheduled to visit Kazakhstan and Tajikistan.
Rice Arrives In Kabul, Then On To Pakistan
Kyrygzstan: U.S. Secretary Of State Rice Talks To RFE/RL
Kyrgyzstan: U.S. Secretary of State Calls For Closer Ties