PURPOSE: The aim of this study was to investigate any difference of ultrasound findings for palpable and nonpalpable breast cancers. METHODS: Two hundred breast cancer patients that had undergone preoperative ultrasound and surgery were enrolled in the study. A total of 126 cancers were palpable, and the remaining 74 cancers were nonpalpable. We compared lesion characteristics using ultrasound images according to the BI-RADS(R)-Ultrasound guidelines of the American College of Radiology. A crude odds ratio (OR) and 95% confidence interval (CI) were calculated for a comparison of the palpable and nonpalpable breast cancers. RESULTS: Nonpalpable cancers displayed more often an oval shape (OR=0.35, 95% CI=0.17-0.70), no posterior acoustic features (OR=0.50, 95% CI=0.28-0.89), and a parallel orientation (OR=0.50, 95% CI=0.28-0.89). An irregular shape (OR=2.98, 95% CI=1.60-5.54), a spiculated margin (OR=2.66, 95% CI=1.23-5.74), and a combined pattern of posterior acoustic features (OR=7.20, 95% CI=1.64-31.66) were more commonly observed in the palpable cancers. CONCLUSION: Palpable and nonpalpable breast cancers were found to have different ultrasound characteristics.