Google's profits were up 17% to $1.21bn (£608m) for the three months to the end of December.Some analysts had been hoping for stronger profit growth and its shares fell sharply in after hours trading.
Google's shares have fallen more than 18% so far this year on concerns that the slowing US economy will cause advertisers to cut back on spending.
Investors have become used to Google reporting extremely strong profit growth.Analysts say the latest quarter shows that even Google is not immune to an economic slowdown in the US.
"I think its essentially an in-line quarter for Google which, given the history of beating expectations is disappointing Wall Street.
"There was a slight softness in revenue which perhaps portends softness going forward due to the US economy," said Clayton Moran, senior vice president of the Stanford Group.