Starting with a definition of ethics and deontology, the article analyses the application of these concepts in the field of Library and Information Sciences. One of the characteristics of a profession is the presence of shared values. In LIS these values are based on the respect for human dignity and the principle of moral self-determination. They are set down in a deontological code that testifies to the usefulness of the profession to society. Examples of experiences taken from everyday practices demonstrate the types of ethical conflicts that exist.