The aim of the study is to describe the effect of robot anxiety. The forming of the concept and the description of similar constructs, like technological anxiety and computer anxiety, is presented through a historical review. Given our current knowledge of this topic it seems that cognitive aspects are the key factors underlying robot anxiety. According to literature dissemination of knowledge appears as the best way to lower anxiety. Attempts to develop cognitive therapies are also mentioned. As presented a widely accepted instrument for the measurement of robot anxiety is yet to be developed. RAS and NARS are introduced as possible scales as they are often adapted to studies although both leave things to be desired. The "Uncanny Valley" is also discussed, as it can explain how the appearance of robots affect the approval they gain from people, thus emphasising the importance of the design of robots.