It was widely speculated that his declining health was the reason for him stepping down.
Jobs had previously taken medical leave in January, but did not specify why. In 2009, Jobs took a six-month medical leave to have a liver transplant. Jobs took two months off in 2004 while recovering from surgery for pancreatic cancer.
Apple released a statement Wednesday:
"Apple has lost a visionary and creative genius, and the world has lost an amazing human being. Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and an inspiring mentor. Steve leaves behind a company that only he could have built, and his spirit will forever be the foundation of Apple.
"If you would like to share your thoughts, memories, and condolences, please email email@example.com," the statement said.
Steve Jobs' family released a statement Wednesday:
"Steve died peacefully today surrounded by his family.
"In his public life, Steve was known as a visionary; in his private life, he cherished his family. We are thankful to the many people who have shared their wishes and prayers during the last year of Steve's illness; a website will be provided for those who wish to offer tributes and memories.
"We are grateful for the support and kindness of those who share our feelings for Steve. We know many of you will mourn with us, and we ask that you respect our privacy during our time of grief."
Apple co-founder Steve Wozniak said "I'm shocked and disturbed" when he learned the news.
Microsoft co-founder Paul Allen said Wednesday: "My condolences to Steve Jobs' family and friends. We've lost a unique tech pioneer and auteur who knew how to make amazingly great products."
Microsoft co-founder Bill Gates released a statement Wednesday:
"I'm truly saddened to learn of Steve Jobs' death. Melinda and I extend our sincere condolences to his family and friends, and to everyone Steve has touched through his work.
"Steve and I first met nearly 30 years ago, and have been colleagues, competitors and friends over the course of more than half our lives.
"The world rarely sees someone who has had the profound impact Steve has had, the effects of which will be felt for many generations to come.
"For those of us lucky enough to get to work with him, it's been an insanely great honor. I will miss Steve immensely."
Governor Jerry Brown released a statement: "Steve Jobs was a great California innovator who demonstrated what a totally independent and creative mind can accomplish. Few people have made such a powerful and elegant imprint on our lives. Anne and I wish to express our deepest sympathy to Steve's wife, Laurene, and their entire family."