Rationale and Objectives: To investigate the feasibility of oxygen-challenge blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) at 3T for evaluating the early change of blood oxygenation before and after transcatheter arterial embolization (TACE) in patients with hepatocellular carcinoma (HCC). Materials and Methods: Thirty HCC patients with cirrhosis (HCC group, n = 30) and 30 healthy volunteers (control group, n = 30) were included in this study. Patients in the HCC group underwent BOLD before and 1 month after TACE. Oxygen was administered via a mask. Differences between pre-and post-O-2 T-2* values were evaluated using a pairwise t-test. Analysis of variance was performed to assess the statistical differences in the T-2* values measured in HCC group pre-TACE and post-TACE and in healthy volunteers. Results: In the HCC group, the pre-and post-O-2 T-2* values of the cancerous area before TACE were 26.03 +/- 3.30 and 26.84 +/- 3.42 msec, respectively, and both decreased significantly to 8.67 +/- 1.76 and 8.82 +/- 1.80 msec, respectively, at 1 month after TACE (p < 0.001). The respective pre-and post-O-2 T-2* values of the noncancerous area increased significantly from 14.96 +/- 2.32 and 15.33 +/- 2.28 msec at baseline to 16.38 +/- 2.22 and 16.89 +/- 2.24 msec at 1 month after TACE (p < 0.001). No significant response to BOLD was observed in the control group (p = 0.059). Conclusion: Oxygen-challenge BOLD MRI is feasible to assess post-TACE changes in HCC patients.