A rod-shaped actinobacterium, designated strain RS-16(T), was isolated from a rhizosphere soil and its taxonomic position was determined by a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence analysis indicated that strain RS-16(T) was most closely related to the type strain of Motilibacter peucedani (98.3 % sequence similarity). The cell-wall peptidoglycan contained LL-diaminopimelic acid as the diagnostic diamino acid and N-glycolylated murein. The major whole-cell sugars were glucose, galactose and mannose. The predominant menaquinone was MK-9(H4). The major fatty acids were C18 : 1ω9c and C16 : 0. The DNA G+C content was 73.1 mol%. The phenotypic and DNA-DNA hybridization data showed that strain RS-16(T) ( = KACC 16209(T) = DSM 45622(T)) represents a novel species of the genus Motilibacter, for which Motilibacter rhizosphaerae sp. nov. is proposed. Based on the phylogenetic position determined by 16S rRNA gene analysis and the signature nucleotide set of the 16S rRNA sequence, the genus Motilibacter represents a novel family of the suborder Frankineae, for which the name Motilibacteraceae fam. nov. is proposed.