Previous research suggests that humor has beneficial effects on mood, health status, and pulmonary functioning among healthy adults. However, no previous studies have examined the effects of humor among individuals with chronic obstructive pulmonary disease (COPD), despite the fact that patients with COPD are at risk for impairments in emotional well-being, quality of life, pulmonary functioning, and health status. Two studies were conducted to evaluate the effect of humor among patients with COPD. Study 1 was an acute humor intervention in which participants viewed either a Humorous or Neutral video presentation. Participants were evaluated with pulmonary function tests, heart rate and blood pressure monitoring, and questionnaires assessing affect and state anxiety both before and after the video intervention. The sample included 22 participants (36% male) with a mean age of 67.8 (±8.8) years who exhibited severe airway obstruction [mean forced expiratory volume in 1 second/forced vital capacity ratio (FEV1/FVC)=0.52(±.17)]. Results indicated that functional residual capacity increased in the Humor participants (mean change=0.9 liters, p<.05), but decreased among the Neutral participants (mean change=-0.2 liters, p<.02). In addition, Humor participants exhibited a trend toward increased residual volume. Disease severity predicted change in air trapping following the humor intervention, with increased air trapping exhibited by those with less severe pulmonary disease. Study 2 examined the psychological and health benefits associated with a sense of humor and the use of humor as a coping style among individuals with COPD. The sample included 46 participants (41% male) with a mean age of 66.9(±9.9) who completed one comprehensive assessment of humor, depression, trait anxiety, affect, quality of life, and recent infectious illnesses. Correlational analyses revealed that a humorous coping style was associated with decreased depression (r=-.47, p<.001), diminished anxiety (r=-.51, p<.001), decreased negative affect (r=-.32, p <.04), improved positive affect (r=.46, p<.01), enhanced quality of life (r=.57, p<.001), and fewer days with an infectious illness (r=-.34, p<.02). Sense of humor was correlated with decreased anxiety (r=-.39, p<.01) and improved positive affect (r=.35, p<.02). These studies offer preliminary evidence that individuals with COPD may reap psychological and health benefits from having humorous personality attributes, particularly a humorous coping style. However, laughing aloud may cause acute decreases in pulmonary functioning by increasing the amount of trapped air in the lungs.