Worldwide sales of smartphones running Symbian totaled 80.9 million in 2009, up from 72.9 million a year earlier.
Because total smartphone sales grew faster, to 172.4 million from 139.3 million a year earlier, Symbian's market share declined to 46.9 percent, Gartner said.
Second-place RIM's market share rose to 19.9 percent from 16.6 percent in 2008.
Microsoft's smartphone OS dropped to the fourth spot as its market share fell from 11.8 percent to 8.7 percent, and sales dropped by about 1.5 million phones.
The launch of a new version, Windows Phones 7 Series, appears to make it a more competitive platform, but as phones based on the rewritten OS won't show up until late this year, sales will continue to struggle during most of 2010, according to Roberta Cozza, principal research analyst at Gartner.
Linux - in which Gartner includes LiMo, but excludes Android - also continues to struggle in the smartphone market. Its share dropped from 7.6 percent to 4.7 percent in 2009.
Android was only the sixth largest smartphone platform in 2009, with a market share of 3.9 percent. However, that looks likely to change soon.
Android phone sales really started to pick up during the fourth quarter. Four million out of a total 6.8 million units were sold during the last three months of 2009.
Palm's WebOS is a newcomer on Gartner's list in seventh place, with a 0.7 percent market share.
While the smartphone market is booming, total worldwide mobile phone sales of 1.2 billion units were down about one percent compared to 2008, according to Gartner.
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