The paper reports on the development of an instrument enabling researchers to examine organizational culture at schools. The study is related to a comprehensive educational research project investigating the efficiency of schools as organizations with unique characteristics. The large-scale project is based on the analysis of organizational culture and, more specifically, organizations' attitude towards change. The paper first presents the results of a preliminary phase consisting of a questionnaire study on organizational culture at schools. Then these results are compared with the data obtained through a questionnaire based on Quinn's Competing Values Framework. Finally, an attempt is made to draw a comparison between the 'value map' revealed by the questionnaire examining organizational culture and the basic bipolar model of schools.