The Japan international joined the Bundesliga side in June 2010 after opting to leave Kashima Antlers in his homeland.
Uchida has since become an important part of Schalke's first-team squad and the 26-year-old has prolonged his stay until June 2018.
"Schalke is a very special club with wonderful fans who have always supported me in the last few years," he told the club's official website.
"The atmosphere in the Veltins Arena is outstanding. I want to thank our supporters for their confidence."
Schalke general manager Horst Heldt was delighted to tie Uchida to an extension.
"We have achieved our goal," he said. "Atsuto is another player at the club who is extremely reliable and plays at a consistently good level for a long time."
Uchida has made 132 competitive appearances for Schalke and lifted the DFB-Pokal with the club in 2011.
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