This paper is a study of 40 cases of sensory-motor conversion reaction over a 5-year period. The results indicate that the choice of symptom site is influenced by certain factors: (1) Previous lesion. The site is most often the area or limb in which previous lesion, injury or organic defect is present. (2)Suggestion. The site and character of the symptom are influenced in particular by iatrogenic suggestion as a result of repeated medical examination. (3)Dominant side. Generally the conversion symptom is manifested on the dominant side. Finally, in addition to recognizing the importance of personality trends, it was observed that the appearance of the symptom in all cases was preceded by an inter-social or inter-personal conflict which was traced through a thorough case history.