At that time Czartoryski was beginning to suffer from weak health. In 1765 he and his private doctor Nathanael Matthaeus von Wolf went to Spa, Belgium. In 1766 he tried to take part in the new Sejm, but because of poor health his influence on it was negligible, and he had no influence on the turbulent events in the last months of his life, notably the Radom Confederation and the Repnin Sejm. He died on 1 March 1768 in his palace at Dolsk.