A contractual approach to forming a partnership between doctor and patient is presented in both theoretical and practical terms. Four basic contractual assumptions underly the doctor-patient relationship: both the doctor and the patient have unique responsibilities; the relationship is consensual, not obligatory; both doctor and patient must be willing to negotiate; and each must gain something in the encounters. Clinical examples are used to show practical implications of this model. Although explicit contracts are not needed for all patients, a contractual analysis of doctor-patient interactions helps both participants share the responsibility for patient care.