An instrument was constructed to measure changes in teacher attitudes and beliefs resulting from training in the teaching of the Elementary Science Study (ESS) program. The 40-item, Likert type instrument was administered to a group of 22 elementary teachers attending a three-week National Science Foundation summer institute, on the first morning of their attendance and again on the last afternoon. Analyses of the data revealed that no items showed significant change in the non-preferred direction and that the means of 21 of the 40 items had changed significantly in the preferred direction. Of those items showing no significant change, most were high on the pretest. Analysis by subject revealed that 14 subjects showed significant change in the preferred direction, one showed significant change in the unpreferred direction, and seven subjects showed no significant change. The instrument developed is included in the document. (CS)