This article reports a conversation analytic study of patients' resisting responses after doctors' diagnostic statements. In these responses, patients bring forward information that confronts the doctor's diagnostic information. We examine two turn formats - aligning and misaligning - with which patients initiate resistance displays, and describe conversational resources of resistance the patients resort to: their immediate symptoms, their past experiences with similar illness conditions, information received in past medical visits and their diagnostic expectations that have been established earlier in the consultation.Through the deployment of these resources, patients orient to the doctor's diagnostic information as negotiable and seek to further a shared understanding with the doctor on their condition. The results are discussed with regard to concordance as a process in which patients and doctors arrive at a shared understanding on the nature of the illness and its proper treatment. Our analysis illuminates the mechanisms in interaction in and through which concordance can be realized. Thus, we suggest that concordance can be seen to encompass not only treatment discussion but also the process where participants reach agreement about the diagnosis. The data of the study consist of 16 sequences of patients' resisting responses to diagnosis and is drawn from 86 Finnish primary care visits for upper respiratory tract infections.