On the basis of correspondence between Jean-Emmanuel Gilibert and the King of Poland and Grand Duke of Lithuania Stanislaw August, the article reveals issues of adaptation of a foreign scientist in the late eighteenth-century Grand Duchy of Lithuania. The attention is focused on the life of J.-E. Gilibert, his financial situation, his life and work conditions with the emphasis on health problems and psychological situation of the scientist, as well as the circumstances of his return to France. The research revealed, that one of the most important problems that faced J.-E. Gilibert upon his arrival to the Grand Duchy of Lithuania was the insufficient financing of his life and work. There were problems with his salary as the payments were late by half-year or more. Because of the non-payment of his designated salary, the scientist was forced to borrow with high interest in France and send money to Lithuania. Analysis of the correspondence shows that even upon the ninth year of his arrival to Lithuania, J.-E. Gilibert was still demanding to be paid for the time he was the director of the school in Grodno. J.-E. Gilibert was not satisfied with his living conditions in Grodno. In his contract with Antoni Tyzenhaus it was stated, that J.-E. Gilibert and his family will be provided with the living quarters suited for his status as doctor. However, the scientist was especially unhappy and even shocked that musicians of the town theatre and dancers lived much more comfortably than he did. The environment in Grodno also affected psychological condition of the scientist. J.-E. Gilibert enjoyed sharing his observations and to learn from experience of other researchers. However, he seriously lacked such social ties in Grodno. J.-E. Gilibert suffered from the feeling of isolation because he did not speak Polish and was unable to freely communicate with Grodno inhabitants, except for other foreigners.