The purpose of this study was to construct a brief version of the 40-item Affect Intensity Measure. Since the assumed one-dimensionality of the scale has been criticized lately, special attention was paid to the factor structure of the full and the brief scales. The scales were tested in three different samples: 510 Belgian citizens representative of the Belgian population, and 204 and 166 students of the University of Antwerp. The Short Affect Intensity Scale has 20 items. Mean scores on the original Affect Intensity Measure were 3.68, 3.67, and 3.67 for the three samples, respectively, while for the Short Affect Intensity Scale the following respective mean scores were registered: 3.76, 3.78, and 3.75. Correlations between the original and brief scales were .94, .93, and .93 for the three samples, respectively. Three factors underlie the Short Affect Intensity Scale: Positive Intensity, Negative Affectivity, and Serenity. Furthermore, the scores for the Short Affect Intensity Scale suggest it is reliable and valid.