Eurozone composite PMI rose to 52.9 in January (flash 53.2) from 52.1 in December.
Services PMI edged up to 51.6 (flash 51.9) from 51.
Spain's composite PMI hit a 6 1/2 year peak of 54.8.
Employment has stabilized over the past two months.
"Companies are reporting the strongest growth of business activity for two-and-a-half years, putting the economy on course to grow by 0.5% in the first quarter if this pace is sustained," Markit says.
"Spain and Ireland are now seeing robust growth, undergoing their strongest phases of expansion since 2007, while Italy is also returning to growth and France's business sector is also showing signs of stabilizing," Markit adds.
The euro is flat $1.3512. (PR)