In December 2017, The Hollywood Reporter revealed that Kilmer had gone through a "two-year battle with throat cancer" and that "a procedure on his trachea has reduced his voice to a rasp and rendered him short of breath". In order to speak, Kilmer plugs an electric voice box in his trachea.[74] Due to the cancer, Kilmer underwent chemotherapy and two tracheotomies.[74][75][76][77]
In 2020, Kilmer reported that he had been cancer free for four years and that he uses a feeding tube to feed himself because he can no longer eat.[78][79]
In 2021, after complex work, Kilmer's voice was able to be re-created through AI technology using archival audio of his voice.[80] This technology was used to produce his voice in Top Gun: Maverick.[81]