Apple's iPhone sales fell to the tech giant's financial performance.
The company's revenue fell 5 percent from a year earlier to about $ 84.3 billion in the fourth quarter, with iPhone revenue dropping 15 percent to about $ 52 billion.
The stumbling was already expected after the technology giant warned investors earlier this month that revenue would be about $ 84 billion, lower than expected.
The company blamed the issues in part because of an economic slowdown in China.
Executives said they remain confident that growth in their services business, which includes Apple Pay and the App Store, will boost future performance.
Revenue from the service business jumped 19 percent to a record $ 10.9 billion in the quarter, which ended Dec. 31.
"While it was disappointing to lose our revenue orientation, we managed Apple over the long term, and this quarter's results demonstrate that the underlying strength of our business is deep and broad," said Tim Cook, Apple's chief executive.
Apple's share price has fallen about a third since October amid investor concerns that buyer appetite for iPhones is weakening.
However, the company's shares gained almost 4% on the trading floor after hours on Tuesday, as the company proved more resilient than feared.
Apple said quarterly sales fell more than 25 percent in its Greater China region, which includes Hong Kong and Taiwan, compared with the previous year.
They also fell about 3% year on year in Europe.
But in the Americas – the company's largest region – sales rose nearly 5 percent.
Apple's struggles are not unique.
Global smartphone sales contracted 5% in 2018, according to Canalys, a market analyst firm.