Objective— To evaluate the effect of perioperative and operative variables on survival time in dogs with aortic body tumors. Study Design— Retrospective study. Sample Population— Twenty‐four client‐owned dogs with histologically confirmed aortic body tumor. Methods— Seventy‐eight patient records of dogs seen at the University of Illinois Veterinary Teaching Hospital between 1989 and 1999 with a diagnosis of a heart‐base mass were reviewed. Dogs without histologic conformation of an aortic body tumor were excluded. Age; sex; breed; the presence of pleural effusion, pericardial effusion, or abdominal effusion; evidence of cardiac arrhythmias; evidence of distant metastasis; treatment with pericardectomy; treatment with chemotherapy; and time from diagnosis until euthanasia or death were recorded on a spreadsheet. Cox proportional‐hazard ratios were used to calculate the relationship of risk variables to survival time. Median survival time was determined using life‐table analysis. Results— Twenty‐four dogs met the criteria for inclusion in the study. The median age of dogs with aortic body tumors was 9 years. All dogs had a surgical biopsy performed. Fourteen dogs had a pericardectomy at the time of the biopsy procedure. Of all factors analyzed, only treatment with pericardectomy had a significant influence on survival (P= .0029). Dogs that had pericardectomy survived longer (median survival, 730 days; range, 1–1,621 days) compared with dogs that did not have pericardectomy (median survival, 42 days; range, 1–180 days). This finding was independent of the presence or absence of pericardial effusion at the time of surgery. Clinical Relevance— Dogs that are diagnosed with aortic body tumors may benefit from a pericardectomy at the time of surgical biopsy.