Apple's profit and sales fell short of analysts’ estimates for only the second time since 2003, as customers deferred iPhone purchases while waiting for a new model to be introduced later in the year.
The company’s sales climbed at the slowest pace since mid-2009.
The iPhone and iPad maker also gave lower-than-expected sales and earnings guidance.
Apple reported a quarterly profit of US$8.8bn, or US$9.32 a share.
Sales rose 23% to US$35bn.
Analysts had predicted profit of $10.37 a share on revenue of $37.2bn.
Apple fell to as low as US$565 in extended trading. The shares had slipped less than 1% to US$600.92 at the close in New York. It is up 48% year-to-date.
Apple is predicting further declines in sales and profit for the current period from last quarter.
The company said that sales would fall to ~US$34bn, and that profit would fall to US$7.65 a share. That compares with predictions by analysts for sales of US$38bn and profit of US$10.27 a share.
The 26mn iPhones sold last quarter compares with 28.4mn average prediction by analysts.
"Speculation that Apple is preparing a new iPhone has caused some pause in sales," Apple Chief Financial Officer (CFO) Peter Oppenheimer said on a conference call.
Apple sold 17mn iPads, compared with the 15.4mn projected.