Worldwide handset volumes declined 4.1 percent in 2018 to a total of 1.4 billion units shipped for the full year, according to research firm IDC, which sees a potential for further declines this year.
"Globally the smartphone market is a mess right now," said IDC analyst Ryan Reith.
"Outside of a handful of high-growth markets like India, Indonesia, (South) Korea and Vietnam, we did not see a lot of positive activity in 2018."
Reith said the market has been hit by consumers waiting longer to replace their phones, frustration around the high cost of premium devices, and political and economic uncertainty.
The Chinese market, which accounts for roughly 30 percent of smartphone sales, was especially hard hit with a 10 percent drop, according to IDC's survey, which was released Wednesday.
IDC said the top five smartphone makers have become stronger and now account for 69 percent of worldwide sales, up from 63 percent a year ago.
Samsung remained the number one handset maker with a 20.8 percent share despite an eight percent sales slump for the year, IDC said.
Apple managed to recapture the number two position with a 14.9 percent market share, moving ahead of Huawei at 14.7 percent, the survey found.
IDC said fourth-quarter smartphone sales fell 4.9 percent -- the fifth consecutive quarter of decline.
"The challenging holiday quarter closes out the worst year ever for smartphone shipments," IDC said in its report.
A separate report by Counterpoint Research showed similar findings, estimating a seven percent drop in the fourth quarter and four percent drop for the full year.
"The collective smartphone shipment growth of emerging markets such as India, Indonesia, Vietnam, Russia and others was not enough to offset the decline in China," said Counterpoint associate director Tarun Pathak.