Markit said the flash estimate of the composite index that incorporates indexes for manufacturing and service, came in at 52.1, a 27-month high. In August, the index stood at 51.5.
The flash index could be revised. It incorporates 85 percent of the data that goes in the final PMI estimate.
The estimate for September beat expectations. Economist had predicted a rise to 51.9.
Markit said the flash estimate of the manufacturing PMI for the eurozone came to 51.1, down from 51.4 in August. The flash estimate of the service sector PMI for the region came in at 52.1, up from the 50.7 reading for August.
"An upturn in the Eurozone PMI in September rounds off the best quarter for over two years, and adds to growing signs that the region is recovering from the longest recession in its history," said Markit Chief Economist Chris Williamson.
"It is particularly encouraging to see the business situation improved across the region. Although the
upturn continued to be led by Germany, France saw the first increase in business since early 2012 and elsewhere growth was the strongest since early 2011," he said.