PURPOSE: To determine the features revealed by two-phase spiral CT scanning useful for differential diagnosis between recurrent cancer and benign wall thickening in patients who have undergone subtotal gastrectomy for stomach cancer. MATERIALS AND METHODS: We retrospectively reviewed 25 cases in which wall thickening of more than 1 cm in the remnant stomach after subtotal gastrectomy was revealed by two-phase spiral CT scanning. All cases were confirmed: 11 were recurrent cancer, and in 14, benign wall thickening was demonstrated. We analyzed the CT findings including maximal thickness of the gastric wall, patterns of wall thickening, degree of contrast enhancement seen during the arterial and portal phases, and the presence of perigastric strands. Maximal wall thickness was classified as either more or less than 15 mm, and as either focal or diffuse. We also determined whether lymphadenopathy was present. RESULTS: Mean maximal gastric wall thickness was 18.4 mm in the recurrent cancer group ("group A") and 12.6 mm in the benign group ("group B") . The gastric wall was thicker than 15 mm in 10 of 11 group A cases and in 3 of 14 in group B; wall thickening was focal (n=3) or diffuse (n=8) in group A, and focal (n=13) or diffuse (n=1) in group B, while the enhancement patterns seen during the arterial and portal phase, respectively, were high/high (n=8), low/high (n=1) and low/low (n=2) in group A, and low/low (n=7), low/high (n=4), high/low (n=1) and high/high (n=2) in group B. Perigastric strands were observed in nine cases in group A, but in none in group B, while lymphadenopathy was combined with wall thickening in seven group A cases but in none of those in group B. CONCLUSION: In patients who have undergone subtotal gastrectomy for gastric cancer, two-phase spiral CT findings including maximal thickness of the gastric wall, patterns of wall thickening, degree of contrast enhancement seen during the arterial and portal phase, the presence of perigastric strands, and lymphadenopathy are useful for differential diagnosis between recurrent cancer and benign wall thickening.