Traore, 18, has agreed a four-and-a-half year contract and joins from Association Jeunes Espoirs De Bobo-Dioulasso in his native Burkina Faso.
Part of his country's victorious Africa Under-17 championship winning side in 2011, Traore is now a full international having made his debut shortly before his 16th birthday.
He now has 10 international caps and is likely to play a part in next month's World Cup qualification play-offs in Africa which sees Burkina Faso face Algeria.
Traore was taken on as a Blues trialist before Chelsea's tour of Asia in the summer and played a part in all three games, scoring in Malaysia and Indonesia.
He impressed me a lot in the pre season tour to Asia. Yet another attacking mid, but you always want world class players like this with unlimited potential. Will be interesting to see what we do with him. I imagine a lot of teams are going to inquire about loaning him out.- isildur1