Users attempting to access search saw an error message from the company.
"We are aware that Yahoo Search is unavailable to users. Our engineers are working to restore the service at the earliest," a Yahoo spokeswoman told CNBC.
Bing, a Microsoft service, powers Yahoo's search engine. Bing search cut out for about 20 minutes before it was restored, according to reports.
"This morning, some of our customers experienced a brief, isolated services interruption which has now been resolved," a Microsoft spokesman said.