Monoallelic mutations of GHR have been described in idiopathic short stature (ISS), although the significance of these remain unclear. We report a case of ISS with novel monoallelic S219L mutation of GHR and discuss the possible significance of monoallelic GHR mutation in ISS. The proband, a 13.9-year-old Japanese boy, had severe short stature (-3.8 standard deviation [SD]). Serum insulin-like growth factor (IGF)-I level and growth hormone (GH) secretion was normal. His parents were nonconsanguineous and had normal stature. Genetic analyses revealed a novel monoallelic missense variation in exon 7 of GHR (S219L). The proband's mother had the same variation. S219L might be the novel mutation judging from there being no registration of it as a single-nucleotide polymorphism (SNP) in any database, evolutional conservation of Ser219, in silico analyses, and computational molecular visualization analysis. Furthermore, a review of the literature showed that the median height of missense mutation carriers of GHR was relatively low. We propose the possibility that monoallelic mutation of GHR increases the susceptibility to short stature.