This study attempts to assess university library organizational effectiveness and to develop an instrument to measure the construct. Major findings of the study are as follows. First, organizational effectiveness criteria can be reduced to fifteen factors. Second, four distinct clusters of libraries are identified, each showing a unique effectiveness profile. Third, there are significant differences in dimensions of organizational effectiveness according to the number of users, full-time staff, unit and position to which respondents belong. The investigation shows that organizational effectiveness of university libraries is, indeed, a multidimensional construct, implying that no single measure of effectiveness Is sufficient to describe an organization.