Google Inc said its net revenue grew 29 percent year-over-year to $6.54 billion in the first quarter, above the $6.32 billion expected by analysts.
Shares of Google were down roughly 4 percent at $553.09 in after-hours trade.
The world's No.1 search engine said on Thursday it had net income of $2.3 billion in the first quarter, or $7.04 a share, up from $1.96 billion, or $6.06 a share, in the year-ago period.
Excluding certain items Google said it earned $8.08 a share.
Google said the average cost-per-click for its search ads in the first quarter increased about 8 percent year-over-year and decreased 1 percent from the fourth quarter.
(Reporting by Alexei Oreskovic; Editing by Richard Chang)