Amazon on Tuesday beat first-quarter earnings estimates on strong sales of electronics and media.

The Seattle, Washington, company reported first-quarter net income of $143 million, or $0.34 per share, on sales of $4.13 billion. That beat the Thomson Financial consensus of estimates for the online retail giant to report net income of $141 million, or $0.32 per share, on revenue of 4.08 billion in the quarter.

Amazon's sales increased 37 percent compared with the same quarter a year ago.

"Our sales growth this quarter was driven by low prices and millions of in-stock items available for immediate shipment," Amazon CEO Jeff Bezos said in a statement.

Amazon reported media sales grew 28 percent to to $2.54 billion in the quarter compared with $1.99 billion with the same period a year ago.

Sales of electronics and other merchandise jumped 56 percent to $1.48 billion in the quarter compared with a year ago.