Se presenta un estudio del fenómeno Bullying desde la perspectiva del Hostigador, Hostigado y Testigo en estudiantes de escuelas de nivel inicial de la CABA. Participaron del estudio 966 estudiantes con un rango etario de 11 a 13 años y de ambos sexos, de nueve centros educativos de gestión pública y privada. Por otra parte se analizan las características del escenario o espacio físico donde se produce el hostigamiento. Luego el tipo de comunicación sobre el hostigamiento por parte del hostigado, tanto a amigos, familiares, docentes y adultos en el colegio. Finalmente la actitud de parte del sistema hacia el hostigador, ya sea no actuando sobre el mismo (sin decirle nada), censurándolo o avalándolo. Palabras clave Bullying, Hostigamiento, Hostigador, Hostigado, Testigo, Sexo ABSTRACT EPIDEMIOLOGY STUDY ON BEHAVIOR OF HARASSMENT (BULLYING) IN SCHOOLS OF BUENOS AIRES CITY The present paper analyzes the Bullying phenomena from the perspective of the Bully, Bullied and Witness in high school students of Buenos Aires Autonomous City. The study has been made over 966 students from 11 to 13 years old and from both sexes of nine educative centers of public and private management. Besides the analysis of the characteristics features of the stage scanery or physical space where bullying occurs, the communication about the problem by the harassed by the harassed to friends, family, teachers and adults in the school has been studied. Finally the system attitude of the system to the harasser either not acting on it (without saying anything), censoring or endorsing it. Key words Bullying, Harassment, Bully, Bullied, Harassed, Witness, Sex