Starting from the recent publication of the young Antonio Rosmini’s letters (1813-1819), the author of this paper intends to probe the topic of friendship within the formation of the Roveretan philosopher. In particular, two interconnected aspects will emerge. On the one hand, the relevance of the relationships – often qualified by a deep friendship – in which Rosmini matured both as man and scholar. On the other, starting from the personal experience and the several contents he studied, his high conception of friendship.