Background: In 2016, Kavalieratos and colleagues performed a systematic review of randomized clinical trials (RCTs) of palliative care (PC) interventions. The majority of RCTs included focused on oncology, with fewer in heart failure (HF). Cancer patients' often predictable decline differs from the variable illness trajectories of HF; however, both groups experience similar palliative needs, and accordingly, PC in HF continues to grow. Objective: To investigate if PC interventions differ between cancer and HF patients. Design: In this secondary analysis, we compare PC interventions for cancer and HF patients evaluated in the 2016 systematic review. Settings/Subjects: We included a total of 25 trials, 19 of which included 3730 cancer patients, and 6 of which included 1049 HF patients (mean age, 67 years). Measurements: We compared the following five characteristics among included trials: PC domains addressed, duration, location, provider specialization, and measured outcomes. Results: The content of the cancer and HF interventions was similar. HF interventions tended to include more home-based (50% vs. 37%) and specialty PC interventions (67% vs. 47%), although these results did not reach statistical significance. Both cancer and HF interventions favored longer durations (i.e., more than one month; 79% and 67%). No HF intervention RCTs included caregiver outcomes, whereas 32% of cancer interventions did. Conclusions: There were no substantial differences in content of cancer and HF interventions, although the latter tended to be delivered by PC specialists at home. There is a need for scalable interventions that incorporate the needs and preferences of individual patients, regardless of diagnosis.