Brand extension is a strategy by which marketers use the established brand name to enter into a new product category. However, to assess the efficacy of brand extension, there is a need to develop appropriate scales as the scales developed in other countries are not necessarily appropriate for use in India. The purpose of this study is to develop such scale. Accordingly four brands namely; Dabur®, Reebok®, Rexona® and Samsung® have been selected. All these brands have extended into new categories. This research closely follows the procedure for developing better measure given by Churchill (1979). Drawing on previous literature a seven item scale is constructed. Psychometrics of the scale are tested with the help of data collected in two rounds. The analytical tools used are Cronbach alpha, item to total correlation and exploratory factor analysis. This scale has the desirable reliability and validity properties. Thus, this scale could be used by the aspiring researchers.