The basic tenets of medical ethics are: autonomy of the patient, beneficence, non-maleficence and justice. These are usually interpreted in the light of the practice of clinical medicine but also apply to pathology and laboratory medicine, a field in which there is often no direct patient contact. We wished to evaluate these basic tenets of medical ethics with respect to laboratory medicine and to provide insights into some of the issues that laboratory physicians, in routine practice and in academia, face on a regular basis. This was done by using the published literature related to the topic of medical ethics, with a special focus on laboratory medicine, as well as the authors’ interpretations and opinions, based on their experience. We conclude that the idea of autonomy of the patient or research participant is pertinent with respect to specimens, autopsies and in legal issues such as consent for publication in the media and social media. Beneficence is relevant with respect to laboratory values in reports, financial issues and in research and education. The concept of non-maleficence is important from the point of view of doing no harm, communication with patients and colleagues, reducing/containing error and misdiagnosis in medicine, screening for disease and in over diagnosis. Justice is applicable to issues of distribution of resources and manpower, and their equitable usage. Many of the tenets, however, need to be interpreted in the light of local laws and customs which differ across the world. We conclude with an Oath for pathologists and laboratory physicians. Key words: medical ethics, misconduct, autonomy, beneficence, non-maleficence, justice, informed consent, medical research, oaths