Biopsies of liver masses that prove to be hepatocellular carcinomas (HCCs) are associated with a risk of seeding the abdominal or chest wall with tumor cells. The reported frequency of seeding varies greatly in the literature. We performed a retrospective cohort study in a large integrated health care system to examine rates of seeding in patients with HCC who had targeted liver biopsies, ablations, or both performed by community radiologists. We reviewed pathology and radiology records to determine the occurrence of wall seeding, defined as a chest or abdominal wall lesion along a definite or probable needle tract. A total of 1,015 patients had targeted liver biopsies (795), ablations (72), or both (148). Multiple procedures were done in 284 patients (28%). Six cases of seeding were identified. The rate of wall seeding was 2/795 patients (0.13%; 95% confidence interval [CI], 0.00%-0.60%) if only biopsies were done versus 4/220 (1.82%; 95% CI, 0.05%-3.58%) if ablations were performed (P = 0.01). The rate was 0/72 (0.00%; 95% CI, 0.00%-0.04%) with ablations alone and 4/148 (2.70%; 95% CI, 0.74%-6.78%) if both procedures were done (P = 0.31). Of those with 1 year follow-up (n = 441), the rate of seeding was 2/269 (0.74%; 95% CI, 0.00%-1.77%) if biopsies alone were done and 4/172 (2.33%; 95% CI, 0.07%-4.58%) if ablations were done. In none of the cases was the seeding a proximate cause of death. Conclusion: Biopsies of liver masses are associated with a low rate of wall seeding when performed in a community setting and when they are the sole procedures. Ablations may have a higher rate of seeding, particularly if done with biopsies, but are still rare. (Hepatology Communications 2017;1:841-851).