This thesis is dealing with the subject of a witness in criminal proceedings. It contains an examination of the term of witness, its rights and duties and specificities of a questioning of a witness who is a victim of crimes and a person under the age of 18 years. The thesis is then dealing with possibilities of protection of a witness. There is a presentation of measures ensuring a witness at a questioning and of limits of forcing a witness to testify. The thesis is also dismantling a questioning of a witness in different stages of criminal proceedings, different methods of questioning including videoconferences and briefly also psychological aspects of questioning a witness
