A novel actinobacterial strain, designated SYSU K20354^T, was isolated from a soil sample collected from a karst cave in Shaoguan city, Guangdong province, southern China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were aerobic, Gram-stain-positive and non-motile. On the basis of 16S rRNA gene sequence similarities and phylogenetic analysis, strain SYSU K20354^T was most closely related to Agromyces humatus JCM 14319^T, and shared the highest sequence identity of 98.3 % based on NCBI database. In addition, 2,4-diaminobutyric acid was the diagnostic diamino acid in cell-wall peptidoglycan. The whole-cell sugars were galactose, glucose, mannose and ribose. The major isoprenoid quinone was MK-12, while the major fatty acids (>10 %) were iso-C_{16 : 0}, anteiso-C_{15 : 0} and anteiso-C_{17 : 0}. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, three unknown glycolipids, three unknown phospholipids and two unknown lipids. The draft genome size of strain SYSU K20354^T was 3.96 Mbp with G+C content of 69.7 mol%. Furthermore, the average nucleotide identity and digital DNA–DNA hybridization values between strain SYSU K20354^T and A. humatus JCM 14319^T were 90.3 and 55.6 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU K20354^T represents a novel species of the genus Agromyces , for which the name Agromyces cavernae sp. nov. is proposed. The type strain is SYSU K20354^T (=KCTC 49499^T= CGMCC 4.7691^T).