For learning science, motivational beliefs such as confidence in one's science abilities and liking of science are associated with current and future science achievement, as well as continued interest in science classes and careers. However, there are currently no measures to test young children's motivational beliefs related to science learning. To meet this need, we developed the Puppet Interview Scales of Competence in and Enjoyment of Science (PISCES). We piloted PISCES with 113 kindergarten children in public schools participating in the Scientific Literacy Project (SLP). Factor analysis supported the multidimensional structure of young children's self-related beliefs about learning science. PISCES scales measured Science Liking, Science Competence, and Ease of Science Learning. Correlations among PISCES scales and achievement subtests provided evidence of PISCES's validity. Children's motivational beliefs varied as a function of length of time spent learning science, with competence beliefs associated positively with science experience. There were no gender differences. (Contains 5 tables.)