Pulmonary embolism (PE) occurs frequently among cancer patients, with a spectrum ranging from small, clinically insignificant thrombi to life-threatening massive PE. It is fatal in as many as 14% of cancer patients, primarily by producing right ventricular heart failure and cardiogenic shock. PE diagnosis is difficult because the signs and symptoms imitate other commonly occurring diseases. Clinicians must be able to integrate a wide array of diagnostic imaging tools and laboratory tests to ensure rapid assessment and diagnosis. Risk stratification with the use of cardiac biomarkers and imaging tests to evaluate right ventricular function will identify treatment options. Hemodynamically stable patients can be treated effectively with anticoagulation alone, whereas those with right ventricular dysfunction require an aggressive strategy with thrombolysis, surgical embolectomy, or a catheter-based intervention. When anti-coagulation is contraindicated, a vena caval filter may be deployed. PE treatment must be customized to the individual and consider the existing thrombus burden, presence of underlying cardiopulmonary disease and right side heart dysfunction, and cancer status of the patient. Clinicians should focus on providing adequate thromboprophylaxis in hospitalized cancer patients to avoid PE treatment.