Se propone la construcción de una escala breve del dominio Responsabilidad según el Modelo de los Cinco Grandes. Este rasgo se define como la tendencia a autorregularse y reconoce dos subdimensiones que distinguen aspectos proactivos e inhibitorios de la conducta. Participaron 718 individuos (50.8% mujeres) de Buenos Aires. Se sometieron a juicio experto 20 ítems, de los cuales sólo se conservaron 12. Un estudio factorial confirmatorio mostró un ajuste aceptable al modelo que mide la Responsabilidad a partir de dos factores correlacionados. Adicionalmente, se obtuvieron asociaciones acordes a lo esperado con las variables del Big Five Inventory. El estudio de la confiabilidad de la escala indicó que esta tiene una consistencia interna adecuada. Aunque se trata de un estudio preliminar, se considera que se han recolectado evidencias de calidad psicométricas suficientes para garantizar la medición del Responsabilidad. Palabras clave Responsabilidad - Cinco Grandes - Personalidad ABSTRACT CONSCIENTIOUSNESS OF THE BIG FIVE MODEL: MEASUREMENT BASED ON PROACTIVE AND INHIBITORY ASPECTS OF BEHAVIOR. The construction of a brief scale of the Conscientiousness domain is proposed according to the Big Five Model. This trait is defined as the tendency to self-regulate and recognizes two subdimensions that distinguish proactive and inhibitory aspects of behavior. 718 individuals (50.8% women) from Buenos Aires participated. Twenty items were subjected to expert judgment, of which only 12 were retained. A confirmatory factorial study showed an acceptable fit to the model that measures Conscientiousness based on two correlated factors. Additionally, associations will be established according to what is expected with the variables of the Big Five Inventory. The study of the reliability of the scale conditional that it has adequate internal consistency. Although it is a preliminary, it is considered that sufficient psychometric quality evidence has been collected to guarantee the Conscientiousness measurement study. Keywords Conscientiousness - Big Five - Personality