Ten Cate has reportedly sealed a three-year deal worth around £1.8million a season after Chelsea agreed a compensation deal with his former club Ajax earlier this week.
Ten Cate will work under manager Avram Grant and alongside Steve Clarke although Chelsea are still searching for a goalkeeping and fitness coach, together with a scout.
A statement on Chelsea's official website said: "Chelsea Football Club can confirm that Henk ten Cate has joined as assistant first-team coach and we would like to welcome him to the club."