A Gram-negative, aerobic and non-motile rod, designated Y4(T), was isolated from a cucumber leaf from Pinggu District, east Beijing, PR China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Y4(T) was most closely related to Luteimonas aquatica RIB1-20(T) (96.7% 16S rRNA gene sequence similarity). DNA-DNA relatedness between strain Y4(T) and L. aquatica RIB1-20(T) was 42.5 ± 3.9%. The predominant fatty acids were iso-C(15:0), iso-C(17:1)ω9c, iso-C(16:0) and iso-C(17:0). The major ubiquinone was Q-8. The DNA G+C content of the type strain was 69.9 mol%. Based on the evidence above, strain Y4(T) represents a novel species of the genus Luteimonas, for which the name Luteimonas cucumeris sp. nov. is proposed. The type strain is Y4(T) ( = CGMCC 1.10821(T) = KCTC 23627(T)).