PURPOSE: The purpose of this study was to analyze the radiologic findings of primary epiploic appendagitis, with particular attention to the correlation of ultrasonographic, clinical, CT, MR and surgical findings. MATERIALS AND METHODS: Among 14 patients with primary epiploic appendagitis who presented with the rapid onset of a very localized pain and tenderness, we performed ultrasonography in all, CT in eight, and MRI in four of these eight. Surgery was performed in two patients. Follow-up examinations were performed using US, CT and MRI (n=2), US and CT (n=2), US alone (n=2), and with regard to clinical features (n=12). RESULTS: US performed in 14 patients revealed the presence in all of small, well-defined, ovoid, noncompressible hyperechoic (n=12) or isoechoic (n=2) solid masses attached to the colonic wall, without bowel wall change and without communication with bowel lumen. CT performed in 8 patients showed varying hyperattenuating fatty lesions in the same location in the abdomen, without other inflammatory process. MRI findings of four patients were helpful for further evaluation of internal architecture. CONCLUSION: In primary epiploic appendagitis, US findings were sufficiently characteristic to allow accurate diagnosis and valuable for the differential diagnosis of other acute conditions of the abdomen.