GROβ(CXCL2) is a chemokine produced by endotoxin-treated macrophages that mediates inflammation and tumor development. However, little is known about GROβexpression in gastrointestinal stromal tumors (GIST) or the relationship between GROβexpression and clinical attributes of GIST. GROβexpression was examined via immunohistochemical staining of 173 GIST samples using tissue microarray. The relationship between GROβexpression and relevant patient and tumor characteristics was assessed, using chi-square tests. Univariate and multivariate analysis was carried out using the Cox regression method. High GROβcytoplasm staining was detected in 56 (32.4%) specimens; high GROβnuclear staining was detected in 64 (37.0%) specimens. High GROβcytoplasm staining was significantly associated with patients’ age (P=0.043) and tumor location (P=0.014), while high GROβnucleus staining was significantly associated with mitotic index (P=0.034), tumor location (P=0.049), and AFIP-Miettinen risk classification (P=0.048). Kaplan-Meier survival curves showed GIST patients with low GROβcytoplasm expression (P=0.023) and mitotic index < 6 per 50 HPFs (P=0.026) to have a more favorable prognosis. These findings indicate that GROβexpression correlates with malignant GIST phenotypes and could be an unfavorable prognostic marker in patients with GIST.