The striker will complete his move to the Valley for an undisclosed fee.
The former Manchester United and Leeds United striker was one of the top marksmen in League One last term, finding the net 25 times in all competitions for the Town having moved to Wiltshire in September 2015.
Ajose enjoyed a prolific loan spell at SN1 during the 2013/14 campaign before leading the scoring charts for Swindon last season. At the end of 2015/16, he was named in the Football League Team of the Season and was shortlisted for the League One Player of the Year award. He was also crowned the Junior Robins’ Player of the Season at their end of season party.
Everyone at Swindon Town would like to thank Nicky for his service to the football club and wish him all the best in his future career.