The relationship horses have with humans is of the highest importance for their use. In the present study in order to investigate relationships of adult horses to humans, a simple evaluation test and scores based on observations was developed. The first reactions of 224 adult horses to the presence of an experimenter were observed and scored. All the horses belonged to the same riding school, had the same general housing conditions and were all geldings. The evaluation was based on the horse’s posture. Individual differences that could be related to some extent to the breed but also to human factors emerged clearly. French saddlebreds showed more often friendly behaviour than Angloarabs, whereas thoroughbreds were more indifferent. It was clear that variations occur between groups of horses depending on different caretakers. In this school, one caretaker was responsible for the whole daily management of a group of horses and is probably a very important factor in their well-being. The effects of this daily relation to a human seemed to be involved in the reactions to a strange person. Further studies are required to investigate what, in practice, may be determinant.