An outbreak of dengue in the Municipality San Jose of Guaribe, Guarico State about the middle of September and to beginning October 1990 is reported. A total 97 cases without death and the Serologic study in a population sample showed type 2 virus. The quick intervention, the effectiveness of the measures of control, one attention medical opportune and the early Serologic diagnostic to contribute of the outbreak control. This is the first description of a dengue outbreak in the Guarico State, Venezuela.