The enhancement pattern of hepatic metastases from colorectal cancer on CT arteriography (CTA) was evaluated in 79 cases with 405 lesions. Sixty-two percent of overall lesions irrespective of size showed ring-like enhancement, and 33% of lesions less than 1 cm in diameter showed homogeneous enhancement. In pathological examination of 59 resected lesions, the enhancement pattern on CTA had a good correlation with the extent of tumor cellularity, necrosis or fibrosis in the lesions. And in 8.5% of resected lesions, the extent of enhancement on CTA was larger than that of perfusion defect on CT arterial portography, which was almost equal to the size in the resected specimen. In such lesions, the enhancement on CTA might include enhancement of normal hepatic parenchyma around the lesion.