Despite the clinical and genetic significance of macrotrabecular-massive hepatocellular carcinoma (MTM-HCC), its imaging findings have not been described. This study aimed to characterize the imaging findings of MTM-HCC by gadoxetic acid-enhanced magnetic resonance imaging (MRI) and evaluate the diagnostic accuracy and prognostic value of these findings.We enrolled three independent cohorts from two tertiary care centers. The three cohorts consisted of a total of 476 patients who underwent gadoxetic acid-enhanced MRI and surgical resection for treatment-naïve single HCCs. Independent review of histopathology and MRI by two reviewers was performed for each cohort, and inter-reader agreement was evaluated. Based on the result of MRI review in the training cohort (cohort 1), we developed two diagnostic criteria for MTM-HCC and evaluated their prognostic significance. The diagnostic performance and prognostic significance were validated in two validation cohorts (cohorts 2 and 3).We developed two diagnostic MRI criteria (MRIC) for MTM-HCC: MRIC-1, ≥20% arterial phase hypovascular component; MRIC-2, ≥50% hypovascular component and two or more ancillary findings (intratumoral artery, arterial phase peritumoral enhancement, and non-smooth tumor margin). MRIC-1 showed high sensitivity and negative predictive value (88% and 95% in the training cohort, and 88% and 97% in the pooled validation cohorts, respectively), while MRIC-2 demonstrated moderate sensitivity and high specificity (47% and 94% in the training cohort, and 46% and 96% in the pooled validation cohorts, respectively). MRIC-2 was an independent poor prognostic factor for overall survival in both training and pooled validation cohorts.With gadoxetic acid-enhanced MRI findings including arterial phase hypovascular component, we could stratify the probability of MTM-HCC and non-invasively obtain prognostic information.