Materials and Methods: In 28 patients with 36 HCCs larger than 1 cm, Mn-DPDP-enhanced T1-weighted fast multiplanar spoiled gradient-recalled echo (GRE) MR images were obtained before and 15 mins after Mn-DPDP administration. Qualitative analysis focused on signal intensity (hyper-, iso-, or hypo-) relative to surrounding liver parenchyma, while the signal enhancement ratio [ER (%)] and lesion-to-liver contrast-noise ratio (CNR) were determined quantitatively. Signal intensity relative to surrounding liver parenchyma, lesion-to-liver CNR and signal ER of the lesions were correlated with their size and histopathologic grade. Results: The imaging procedure showed that relative to surrounding liver parenchyma, 74% (14/19) of HCCs 1-3 cm in size but 47% (8/17) of those larger than 3 cm were hyperintense. There was, however, no significant difference between the two groups (p>0.05). In addition, 35% (6/17) of HCCs larger than 3 cm but none of the 19 smaller lesions were hypointense, with a significant difference between the two groups (p<0.05). Signal ER of the 1-3 cm lesions was significantly higher than in the larger lesions (p<0.05), and in well and moderately differentiated HCCs was significantly greater than that in those that were poorly differentiated (p<0.05). Differences in lesion-to-liver CNR the two groups were not statistically significant (p>0.05). Conclusion: At Mn-DPDP-enhanced MR imaging, HCCs 1-3 cm in size showed greater signal intensity and signal ER than HCCs larger than 3 cm. Well or moderately differentiated HCCs showed greater signal ER than those that were poorly differentiated. Lesion-to-liver CNR did not differ according to lesion size and histopathologic grade.