The concept of informed consent has evolved over the past century. Today it is a mainstay of clinical practice and human subjects research. This article traces informed consent from its origins in law and bioethical thought to the creation of codes and a system of regulations. In this discussion, informed consent as a point of law and as an ethical construct is viewed from historical and contemporary perspectives in conjunction with the experiences of vulnerable population groups. This consideration does not extend to the use of specific research methodologies. The need to recognize the influence and importance of the sociocultural context in the implementation of informed consent is strongly supported. A correlation is drawn between aspects of consent and the ethical principles of beneficence, nonmaleficence, and autonomy. Four major guidelines for nurse researchers and clinicians are presented.