The Home Depot said hackers stole more than 50 million of its customer email addresses earlier this year, in addition to customers' payment card data.
The U.S.-based retail giant disclosed the new information Thursday in a regulatory filing following up on a data breach the company reported in September that gave hackers access to 56 million debit and credit cards.
The company said the emails and payment information were not linked in the files exposed to hackers.
Home Depot said the data breach occurred between April and September. Hackers used a username and password linked to a contractor to enter the retailer's computer network.
The company is warning U.S. and Canadian customers to be on the lookout for unsolicited emails requesting sensitive personal information.
The new disclosure makes this data breach larger than the one that occurred at Target stores during the run-up to Christmas 2013.