The objectives of this study were to determine the prevalence of dyspnea in the general cancer population, the intensity of the symptom as perceived by the patient, and the patient characteristics associated with the presence of dyspnea. Nine hundred and twenty-three cancer outpatients completed visual analogue scales (VAS) and verbal rating scales (VRS-D) to assess the intensity of their dyspnea. Baseline data included variables that were known covariates of dyspnea. Forty-six percent of the patients had some shortness of breath. Only 4% had a diagnosis of lung cancer and 5.4% lung metastases. Risk factors found to be significantly related to the presence of dyspnea were history of smoking; asthma or chronic obstructive pulmonary disease (COPD); lung irradiation; or a history of exposure to asbestos, coal dust, cotton dust or grain dust (P values from 0.001 to 0.038). The prevalence of dyspnea was strongly related to the number of risk factors a patient had (P < 0.0001). The VAS and VRS-D were significantly correlated, establishing concurrent validity for the VRS-D.