Among a significant number of existing polymorphisms of the COL1A1 gene, the most studied is the polymorphism in the transcription initiation site SpI (+1245 G/T, rs1800012), and the heterozygous polymorphism of the COL1A1 gene determines the degree of bone mineral density reduction and, accordingly, linear bone growth. The +1245G/T polymorphism of the COL1A1 gene in children with growth hormone (GH) deficiency was investigated by polymerase chain reaction. A genetic study of 28 children (21 boys, 7 girls) with GH deficiency was performed. The age of the children was 10.86 ± 3.15 years, and the growth retardation was -2.34 (±0.85) SDS. At the time of the study, the children were in a state of euthyroidism. They had a polymorphism of the COL1A1 gene, namely +1245 G/T (rs1800012). In the group of patients with GH deficiency, the proportion of the T/G genotype was 1.4 times higher than in the controls. The presence of homozygous TT and GG genotypes can be protective against GH deficiency (OR = 0.38, 95%CI 0.08-1.79; P = 0.22 and OR = 0.99, 95%CI 0.40-2.18; P = 0.88, respectively). The ratio of allele frequencies in children with GH deficiency (pT = 0.268, qC = 0,732) was significantly different from 1:1, indicating a bias in the study group, possibly due to small sample size. The allele frequencies in patients with GH deficiency were practically indistinguishable from the control group, and the distribution of genotypes corresponded to the Hardy-Weinberg equilibrium. The main allele in the control group was G (pT = 0.693), as well as in the group with GH deficiency (pT = 0.732). Thus, in children with GH deficiency, carrying the G allele of the polymorphic locus +1245G/T (rs1800012) of the COL1A1 gene prevails, which may be a prerequisite for the development of this pathology.