The ALA Code of Ethics was adopted in 1939
"Adopted at the 1939 Midwinter Meeting by the ALA Council; amended June 30, 1981; June 28, 1995; and January 22, 2008.
As members of the American Library Association, we recognize the importance of codifying and making known to the profession and to the general public the ethical principles that guide the work of librarians, other professionals providing information services, library trustees and library staffs.
Ethical dilemmas occur when values are in conflict. The American Library Association Code of Ethics states the values to which we are committed, and embodies the ethical responsibilities of the profession in this changing information environment." Read the Code of Ethics Online
"The Code of Ethics of the American Library Association has a long history. ALA adopted its first official code of ethics in 1939. The code was revised in 1981, in 1995, and again in 2008. As noted by John A. Moorman in 1995:
Since its formation, the American Library Association has worked on a Code of Ethics for its membership. In 1903, 1929, 1938, 1975, 1981, and since 1992, special attention has been given to either formulating, revising or revisiting the American Library Association Code of Ethics. The Association’s Code of Ethics Committee was first noted in 1928 and was established as an ALA Council standing committee in 1975" Read more from the History of the ALA Code of Ethics.