The National Association of Realtors reported that existing home sales increased 4.9 percent to an annual rate of 4.89 million units. May's increase was the largest since August 2011.
April's pace was revised up to a 4.66 million units from the previously reported 4.65 million units.
Economists polled by Reuters had forecast sales rising 2.2 percent to a 4.73 million-unit pace last month.
The housing recovery stalled in the second half of 2013 as interest rates increased and prices surged against the backdrop of a dwindling supply of properties available for sale.
Despite the consecutive months of gains, sales were down 5.0 percent compared to May last year. They remain down 9 percent from a peak of 5.38 million units hit in July.