The newly appointed Blues boss admits it would be "fantastic" to recruit a couple of new players, with the club moving for Roma's Daniele De Rossi and Vitesse's Marco van Ginkel
The 50-year-old, whose return to Stamford Bridge was announced on Monday, has vowed to improve the Blues this season and says it might take a couple of signings to do so.
Chelsea have opened preliminary talks with Roma to sign Daniele De Rossi and are also in the process of securing the services of Vitesse midfielder Marco van Ginkel.
"If we can improve the team by buying a couple of players it is fantastic but I have to improve the team and the players with my work. That's a priority, improve," Mourinho told Chelsea TV.
While Mourinho is eager to bring in several new faces, he admits the work he does on the training ground is just as important as signing new players.
"We have to improve the team, and when I say improve the team people are already thinking about how many millions Chelsea are going to spend, and when I say improve the team I am saying improving by work," the Portuguese boss continued.
"My work has to improve players and improve the team. If I don't do that I am not happy with myself."
Along with the changes at Stamford Bridge, Manchester United and Manchester City will also be under new management for next season and the former Real Madrid and Inter coach says it is a very exciting time for the Premier League.
"I still think the Premier League is a fantastic competition and I don't know but I believe there will be five or six very strong teams," Mourinho added.
"In my time here in 2004 it was more about us, Manchester United and Arsenal, and after that a gap to the other teams.
"In this moment I think you can put five or six teams in the same plan, aiming at the start to reach the Champions League spots which is very difficult and with more ambition to win the Premier League, and so the competition will be fantastic. I hope I can beat the competition."