The leading e-tailer's site was down for about 30 minutes starting about 2:40 p.m. PST. All areas of the site were inaccessible, including its books and music stores and its auctions area.
"We're sorry, but our store is closed temporarily. We expect to be back soon," Amazon said in a note to customers. "We apologize for the inconvenience, and thank you for your patience."
As of 3:10 p.m. PST, the site was again accessible. Amazon representatives were not immediately available to comment on the length of the outage or its cause.
The Seattle-based e-tailer suffered three similar outages in November. Unlike today's outage, customers during those downtimes could still get to Amazon's auctions and zShops.
Amazon was also one of several sites that came under attack last month in a rash of distributed denial-of-service attacks. At that point, the company's site didn't actually experience an outage, but it was so clogged with traffic from the attacks that it could not respond to most consumer requests.