This report is about a study undertaken by the Hong Kong International Association for the Evaluation of Educational Achievement centre for the Second International Science Study (SISS), of which included a large scale survey using stratefied samples of 5,352 primary 4 students and 4,981 junior secondary 2 students. Cognitive instruments were being employed to measure the science acheivements of Hong Kong students. Findings suggest low and poor achievements for primary 4 and junior secondary 2 samples, respectively.