Elderly patients with acute pulmonary embolism (PE) have higher mortality than non-elderly patients, but receive systemic fibrinolysis less frequently. In this sub-analysis of the SEATTLE II trial, we evaluated the efficacy and safety of ultrasound-facilitated, catheter-directed, low-dose fibrinolysis in elderly patients with submassive and massive PE. We compared patients ≥65 years old with those <65 years old. Eligible patients had proximal PE and a right ventricular-to-left ventricular (RV/LV) diameter ratio ≥0.9 on chest computed tomography (CT). The primary efficacy outcome was the change in chest CT-measured RV/LV diameter ratio at 48 hours after procedure initiation. The primary safety outcome was major bleeding within 72 hours. Sixty-two patients were ≥65 years of age and 88 were <65 years of age. The RV/LV diameter ratio decreased in both groups 48 hours post-procedure, with a mean change of −0.47 in those ≥65 and −0.39 in those <65 years old, with no difference between groups (p = 0.31). Major bleeding occurred in nine (15%) of those ≥65 and in six (7%) of those <65 years old (p = 0.17). Ultrasound-facilitated, catheter-directed, low-dose fibrinolysis resulted in a similar reduction in RV/LV diameter ratio in elderly patients with massive and submassive PE compared with non-elderly patients.