Purpose: The purposes of this study were to determine the intertester and intratester reliabilities of the Lateral Scapular Slide Test (LSST) method, and to examine if significant differences existed in scapular positions among the pain groups (right-shoulder pain group, left-shoulder, pain group and both-shoulders pain group). 27 female subjects (mean age = 51.6, mean height = 157.7 cm, mean weight = 57.5 kg) with shoulder pain were recruited for this study. Methods: The bilateral distances between the root of the scapular spine and T3/4 (RSS), and between the inferior scapular angle and T7/8 (IA), were recorded. Subjects were tested at three positions: the with arms with abducted at 0, 45 and 90 degrees in the coronal plane. The LSST measurements were performed by two testers, selected randomly. Results: The results were as follows: Intraclass correlation coefficients (ICCs) for the intertester reliability were excellent (ICC 0.78-0.94). And the ICCs for the intratester reliability were excellent (ICC 0.83-0.99). In the right-shoulder and both-shoulders pain groups, the right-side RSS and IA values of right side were significantly greater than of the left-side RSS values left side for the arms abducted at 0 degrees of right shoulder pain group and both shoulder pain group (p<.05). However, the side-to-side difference was less than 1.5 cm. Conclusion: Our results suggest that the LSST is highly reliable in identifying the abnormal scapular position of patients with shoulder problems. Future research should be continued to clarify the clinical usefulness of this method.