Korean students ranked the 3rd out of 32 participating countries in the first cycle of PISA(Programme for International Student Assessment) science field, which assessed 15-years-old students' scientific literacy. PISA developed several variables such as parents' socio-economic status, parents' educational attainment, family wealth, and cultural possession, to investigate the effects of background variables on scientific literacy. On the other hand, motivation and engagement in science study were not given much attention, partly because science was the minor area in the first cycle of PISA. Therefore, PISA Korea developed a series of variables to collect data on students' learning motives and out-of-school activities in science as a national option. The results are as followings. First, Korea was found to be one of the PISA participating countries with the scientific literacy achievement least influenced by parents' socio-economic status, family wealth, and parents' cultural possession. Second, the degree of achievement in scientific literacy according to parents' educational attainment was in a positive correlation, similar to the overall tendency of PISA. Third, the most crucial learning motive for Korean students was their desire to develop scientific thinking abilities or obtain science knowledge. On the other hand, choosing jobs in the field of science or parental expectation was the least important learning motive. In particular, the motive for scientific learning was found to have a positive relationship with the degree of scientific literacy achievement. Therefore, the higher the students achievement, the stronger the motive for scientific learning in order to develop their ability to think scientifically or acquire science knowledge. Fourth, Korean students were shown to participate very little in out-of-school scientific activities other than watching TV programs related to science. Whatever the activities may be, the more actively involved students are in out-of-school scientific activities, the higher their scientific literacy achievement. Fifth, Korean girls were rather passive compared to boys in all areas, including science learning motive and out-of-school scientific activities. The gender difference was especially more pronounced in out-of-school scientific activities with wider gaps in such activities as reading scientific books or articles and visiting science-related web sites.