They will come in two display sizes. The 21.5-inch version starts at $1,299, and the larger one at $1,799. They will be available in December.
As he introduced the new iMacs, he showed on a giant display how the iMac has shrunk over the years.
Schiller teased audience by talking about the Mac Mini, not an iPad Mini.
"You knew there would be something called 'mini' in this presentation," he said to laughter.
A new Mac Mini starts at $599 and comes with 4 gigabytes of RAM, or working memory, and a 500 GB hard drive for storage. A $999 version comes with a terabyte hard drive, or double the capacity.
After touting growth in Mac computers at a time when sales of Windows-based machines are slowing, Apple introduced a new MacBook. In June, Apple introduced a MacBook Pro that is about as thin as its already-slim MacBook Air, but with a sharper display. That model had a 15.4-inch screen.
At Tuesday's event, Schiller unveiled a smaller version, with a screen of 13.3 inches. He noted that the 13.3-inch MacBook Pro that Apple already makes has been the company's top-selling laptop. The new version adds the sharper display and is thinner and lighter than the regular MacBook Pro.
"In typical Apple fashion, we are going to take our best product and introduce something better and much cooler," he said.
The starting price is $1,699.
Cook began the presentation with a customary update on past products.
Cook talked about the success of the iPhone 5 and the new iPod Touch, both released last month. He said there have been 3 million iPod Touches sold.
He also talked about an upgrade to Apple's software for mobile devices, iOS 6. He said there were now 200 million devices running iOS 6.
He said the app store had more than 700,000 apps, including 275,000 for the iPad. Customers have downloaded more than 35 billion apps, he said.
He touted an e-book app called iBooks and announced a new version with a new reading option: continuous scrolling. With that, you keep scrolling down the screen rather than flip pages to keep reading. You can also tap on a quote to share instantly on Facebook or Twitter.
The event opens with Cook appearing on stage. "We have some fond memories here, and we're going to create a few more today," he told the audience.
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