OBJECTIVES: The aim of this study was to investigate of salivary gland dysfunction with single-photon emission computed tomography/computed tomography (SPECT/CT), especially the relationship between maximum standardized uptake value (SUVmax) of salivary glands and their dysfunction. METHODS: Five patients (2 submandibular sialolithiasis, 2 Sjögren's syndrome, and 1 parotitis) who underwent SPECT/CT were included in this study. The salivary gland excretion function was defined as A (pre-stimulatory 20 min after injection of Tc-99m pertechnetate)/B (post-stimulatory 40 min after injection of Tc-99m pertechnetate) using SUVmax of parotid and submandibular glands. RESULTS: SUVmax before stimulation of the submandibular gland with sialoliths in a patient was lower than that in the opposite submandibular gland without sialoliths (5.81 vs 51.37). Furthermore, the A/B using SUVmax in the other patient of submandibular glands with sialoliths was lower than that in the opposite submandibular glands without sialoliths (0.70 vs 1.85). The A/B using SUVmax of right and left parotid gland in a patient with Sjögren's syndrome was 1.06 and 0.74, respectively. Furthermore, the A/B using SUVmax of right and left parotid glands in the other patient with Sjögren's syndrome was 3.20 and 4.32, respectively. The A/B using SUVmax of right and left parotid glands in a patient with left parotitis was 2.26 and 1.58, respectively. CONCLUSION: The results of the present study indicate that SUVmax using SPECT/CT seems a useful tool for evaluation of the salivary gland dysfunction.