The official agreement on the accession to the alliance was achieved on Monday, May 24, an Aeroflot spokesperson said.
"The accession to the alliance implies the unification of sales, booking and route systems," she added.
The SkyTeam alliance includes AeroMexico, Alitalia, CSA Czech Airlines, Korean Air (South Korea) and KLM (Netherlands).
SkyTeam offers about 8,200 daily flights to 512 destinations all over the world. The alliance handles 228 million passengers annually.
Russian passengers are expected to gain by Aeroflot's joining the SkyTeam alliance. Now the main Russian carrier has to meet international security and service standards. On the other hand, Aeroflot will have to raise ticket prices by $30-$40 for the same reasons.