Objective: The purpose of this study is to produce insight in the explanations for declining pulmonary rehabilitation given by patients with chronic obstructive pulmonary disease. Setting: The participants were recruited from a hospital in Denmark, among patients hospitalized due to an exacerbation of chronic obstructive pulmonary disease and among stable patients attending an outpatient clinic. Participants: Patients who decline participation in offered pulmonary rehabilitation, who speak Danish, who are able to give informed consent and to participate in a 1-hour interview. Method: The research question was answered through interviews with 19 patients. Data Analysis: The interviews were recorded and transcribed verbatim. The transcripts were analyzed using inductive content analysis. The transcripts were condensed; categories were developed providing different types of explanations for declining pulmonary rehabilitation. Each category was named using a content characteristic word. Results: This study shows that some patients do not remember or recall that they have been offered pulmonary rehabilitation during hospitalization. Especially the oldest patients perceive themselves to be too frail from chronic obstructive pulmonary disease, comorbidity or multimorbidity. The male patients tend to find pulmonary rehabilitation irrelevant because they do not consider themselves ill. Furthermore, the study shows that pulmonary rehabilitation is perceived to be time-consuming and conflicting with daily activities. Conclusions: Patients decline pulmonary rehabilitation because the intervention does not fit their perception of health and because they find that participation in the program may collide with priorities and daily activities.