The author presents the philosophy of Stanisław Lem as Neo-Lucretianism and calls Lem a Lucretius of the 20th century. The paper demonstrates two parallel strains in their thought comprising their views on life and religion. The ascetic hedonism of Lem and Lucretius is found in their renunciation of joys in their personal lives, in the interest in intellectual work, and in the tendency to leave some breathing-space for spending some time with family and friends. They also displayed an irreligious attitude, although it did not seem to concern all religions. They were particularly displeased with such religious views which, in their opinions, propagated false outlooks upon life. Consequently it is interesting to note that their negative opinion on religion went hand in hand with attempts to defend it. Neither Lucretius, nor Lem, criticized personal quests for a better life motivated by religious views. They believed that religion can inspire a creative restlessness of the soul. Lucretius said that gods were necessary for people, Lem called God a 'beneficial power'. Lem also believed that Christianity could provide a system of values that was most consistent with human nature. In saying this he followed the arguments of Schopenhauer and Feuerbach.