The novel was well received by most readers and critics. Two months after publication, all 210,000 copies of the first printing had been sold. The New York Times published two positive reviews of the book: Basil Davenport compared Clarke to Olaf Stapledon, C. S. Lewis, and H. G. Wells, a "very small group of writers who have used science fiction as the vehicle of philosophic ideas." William DuBois called the book "a first rate tour de force that is well worth the attention of every thoughtful citizen in this age of anxiety." Don Guzman of the Los Angeles Times admired the novel for its suspense, wisdom, and beauty. He compared Clarke's role as a writer to that of an artist, "a master of sonorous language, a painter of pictures in futuristic colors, a Chesley Bonestell with words". Galaxy reviewer Groff Conklin called the novel "a formidably impressive job ... a continuous kaleidoscope of the unexpected."
Anthony Boucher and J. Francis McComas were more sceptical, and faulted the novel's "curious imbalance between its large-scale history and a number of episodic small-scale stories." While praising Clarke's work as "Stapledonian [for] its historic concepts and also for the quality of its prose and thinking," they concluded that Childhood's End was "an awkward and imperfect book." P. Schuyler Miller said the novel was "all imagination and poetry," but concluded it was "not up to some of Clarke's other writing" due to weakness in its "episodic structure."
Brian W. Aldiss and David Wingrove wrote that Childhood's End rested on "a rather banal philosophical idea," but that Clarke "expressed [it] in simple but aspiring language that vaguely recalls the Psalms [and] combined [it] with a dramatized sense of loss [for] undeniable effect."
In 2004 Childhood's End was nominated for a retroactive Hugo Award for Best Novel for 1954.