Ultrasound-based surveillance has suboptimal sensitivity for early hepatocellular carcinoma (HCC) detection, generating interest in alternative surveillance modalities. We aim to investigate the association between prediagnostic CT or MRI and overall survival in a contemporary cohort of patients with HCC. Using the Surveillance Epidemiology and End Results (SEER)-Medicare database, we analyzed Medicare beneficiaries diagnosed with HCC between 2011 and 2015. Proportion of time covered (PTC) was defined as the proportion of the 36-month period prior to HCC diagnosis in which patients had received abdominal imaging (ultrasound, CT, MRI). Cox proportional hazards regression was used to investigate the association between PTC and overall survival. Among 5,098 patients with HCC, 3,293 (65%) patients had abdominal imaging prior to HCC diagnosis, of whom 67% had CT/MRI. Median PTC by any abdominal imaging was 5.6% [interquartile range (IQR): 0%–36%], with few patients having PTC >50%. Compared with no abdominal images, ultrasound [adjusted HR (aHR): 0.87, 95% confidence interval (CI): 0.79–0.95] and CT/MRI group (aHR: 0.68, 95% CI: 0.63–0.74) were associated with improved survival. Lead-time adjusted analysis showed improved survival continued to be observed with CT/MRI (aHR: 0.80, 95% CI: 0.74–0.87) but not ultrasound (aHR: 1.00, 95% CI: 0.91–1.10). Increased PTC was associated with improved survival, with a larger effect size observed with CT/MRI (aHR per 10%: 0.93, 95% CI: 0.91–0.95) than ultrasound (aHR per 10%: 0.96, 95% CI: 0.95–0.98). In conclusion, PTC by abdominal images was associated with improved survival in patients with HCC, with potential greater benefit using CT/MRI. Regular utilization of CT/MRI before cancer diagnosis may have potential survival benefit compared to ultrasound in patients with HCC.Significance:Our population-based study using SEER-Medicare database demonstrated that proportion of time covered by abdominal imaging was associated with improved survival in patients with HCC, with potential greater benefit using CT/MRI. The results suggest that CT/MRI surveillance may have potential survival benefit compared with ultrasound surveillance in high-risk patients for HCC. A larger prospective study should be conducted for external validation.