"The PMI brings welcome news that the eurozone economy picked up some momentum in October. With new business growing at the fastest rate for six months, firms were encouraged to boost staffing levels again," Markit chief economist Chris Williamson said in a statement.
He warned, however, that job creation "remains insufficient" and that figures suggested the 19-nation eurozone would grow by a still modest 1.5 percent overall in 2015.
Eurozone unemployment in August stood at 11 percent.
The eurozone has been recovering steadily but slowly for the past 18 months helped along by a massive stimulus programme from the European Central Bank.
"This indicates one of the strongest months in the past four years," said Bert Colijn, analyst at ING Bank.
"Most strength came from the service sector, its PMI increased from 53.7 to 54.2. This shows that domestic demand is continuing to lead the European recovery," he said.