Background: There is scientific evidence, but limited, that physicians experience sickness certification tasks as problematic. More knowledge is needed about physicians' own opinions on this matter. Aim: To further describe the experiences of physicians regarding their task of sickness certification. Methods: Qualitative analyses of 622 written responses to an open-ended question on physicians' own opinions about sickness certification given in a comprehensive questionnaire that comprised 83 close-ended items about this matter. The questionnaire was sent to 7665 physicians in Sweden and the response rate was 71%. Results: The physicians stated that they found it difficult to provide sickness certificates and expressed frustration over an altered concept of disease, problems in assessing work capacity, lack of time, labour market issues, limited resources for care and rehabilitation, and lack of management and support in their work. They also felt that their authority has diminished and that it was hard to combine the two roles of being patients' advocate and a medical expert. Consequently, they felt distressed and suggested that several types of changes be made, including transfer of sickness certification tasks to specialized physicians, multi-professional teams, or specialized clinics, and introduction of specific guidelines for certification. Conclusions: Physicians state several types of problems related to sickness certification tasks and many lack support in handling these problems. Such support needs to be improved, and scientifically studied.