The International Tennis Federation says more doping tests will be carried out on professional players this year.
In a joint initiative between the ITF, ATP, Grand Slam Board and WTA, the number of tests this year will increase to 8,000, from 4,899 in 2016. More samples will be placed into long-term storage.
ITF President David Haggerty says "we welcome this strengthening of the sport's anti-doping efforts."
Haggerty says: "Protecting the integrity of tennis is an ongoing priority of the governing bodies of tennis to ensure that tennis is and remains a clean sport, and these enhancements will make a positive contribution to achieving that priority."