The article analyzes the symbols, motifs and images in Mieczysław Jastrun’s poetry to reconstruct his vision of childhood within in a broad philosophical and anthropological perspective, drawing in particular on Gaston Bachelard’s idea of “reveries toward childhood” and Mircea Eliade’s discussion of sacred time and space. In many of Jastrun’s poems the evocation of childhood is associated with a pastoral summer landscape; it is not, however, a specifi c summer, an identifi able moment of his life, but an image representing the essence of childhood. It is an evocation of happiness, security, a promise of future wellbeing, an experience of fullness of being or a communion with nature and a transcendent reality. The interpretation of individual poems clearly point to the conclusion that childhood remains for Jastrun a sacrum, an immanent sacred site. It is, however, also a lost childhood, viewed from the perspective of an adult who has been irrevocably expelled from that Arcadia and has to live in a transient world doomed to death. The longing for the idyllic childhood can be found throughout Jastrun’s verse, nowhere as poignant as in his last volume of poems, completed before his death.