A test of competencies involved in "Science - A Process Approach" that appeared to measure the same behavior required by the American Assoc"ation for the Advancement of Science (AAAS) appraisal activities was constructed and formed the preliminary version of the Elementary Teachers' Science Inventory (ETSI). A criterion instrument based on the AAAS Check Lists of Competencies constituted a 275 item performance test. Both the ETSI and the performance test were administered to 100 elementary teachers from two counties. Results were analyzed and 56 items were selected for the ETSI final version which was administered to another sample of 100 elementary teachers. Teachers were classified as "high", "average" and "low" competency groups on the basis of ETSI score. ETSI predictions were compared with performance test scores and a reliability of .86 was computed. Teacher characteristics used were semester hours of science credit, age, level currently teaching, and years of teaching experience. No significant relationship was found for credit hours, age, or teaching level. Seven per cent of the teachers were classified as "high" competence (90 per cent successful completion), eighty per cent as "average" (75-90 per cent successful completion), and thirteen per cent were "low" competence (less than 75 per cent successful completion). (BC)