Vertebral heart size (VHS) and vertebral left atrial size (VLAS) are common radiographic measurements for assessing cardiac enlargement in dogs. Reference intervals vary among breeds and have not been previously published for Maltese, which are predisposed to cardiac enlargement. This retrospective study described reference intervals for VHS and VLAS in 81 healthy Maltese. Mean VHS (9.5 ± 0.46 vertebrae) and median VLAS (2 ± 1.8-2.1 vertebrae) were lower than previously reported standard threshold values. Measurements were not influenced by sex, age, or weight, and intra- and interobserver agreement was high.