He is being treated at the intensive care unit of the cardiology department of Santaros Clinics in Vilnius.
Professor Landsbergis, aged 92, said he was hospitalised due to low blood pressure contributed by fatigue and the lack of rest, but is preparing to return home.
However, it is unclear when the former leader of the Homeland Union-Lithuanian Christian Democrat party (TS-LKD) would be discharged from the hospital.
Vytautas Landsbergis is the de facto first head of state of Lithuania since the restoration of its independence in 1990.