Spokeswoman Danielle Rhodes Ha says the newspaper is looking into the cause. The company offered no further details.
The website went down late Wednesday morning and continues to be inaccessible.
The company's newspaper and corporate sites also appeared to be unreachable. Emails sent to New York Times email addresses were returned as undeliverable.
"The New York Times Web site is experiencing technical difficulties. We expect to be back up shortly," said the Times in a message sent from its official Twitter account just before noon on Wednesday.