A robot is considered to be any automated multipurpose machine that can perform certain tasks in the same way a human being can. Today, robots are used in various fields where they are used for assistive, industrial, hospitality and health purposes. Also, rapid advancement of modern technology in the last few decades allows robots to have functions that are similar to human behavior – eye contact, joint attention, touch. Thanks to this and to the understanding that children with autism spectrum disorder (ASD) show great interest in using electronic devices and like to interact with robots, the number of researches related to the use of robots in the diagnostic process and therapy is on the rise. This review paper will review available research on the use of robots in the diagnostic and therapy process of children with ASD. Efforts will be made to assess whether there are robots whose characteristics make them more efficient than others in their tasks. Furthermore, the purpose is to determine whether there are some developmental domains (e.g., joint attention, imitation, stereotypical behaviors, or language skills) that can be better rehabilitated when using a robot compared to the traditional rehabilitation which requires a human therapist. Robots and autism spectrum disorder are described first within this paper, followed by their use in diagnostic process and therapy in children with this disorder. A review of the literature shows that previous research has focused more on the area of use in therapy, and to a lesser extent in diagnostics which is expected given the current technological possibilities. Also, the results show that subjects with ASD had better performance in the domain of social interaction and communication while working with the robot compared to the one with a clinician. They were also better in directing behaviors toward the robot and maintaining attention during the tasks. In addition, there are indications that the use of robots is effective in reducing the amount of stereotypical and repetitive behaviors and improving verbal performance in individuals. Although the conducted research has certain shortcomings (absence of control groups, small samples, predominantly male subjects), it is important to continue to study this area and develop it in order to optimally use the potential of modern technology in the rehabilitation of children with ASD.