The purpose of this study was to explore alignment between reform-based Turkish primary science curriculum and alternative assessment practices of a classroom teacher. Observational case study approach was utilized. A classroom teacher with 32 years of experience and his 31 students participated in the study. The data were collected during one academic year via classroom observations, teacher interviews, instructional materials and a science teaching belief instrument. Analysis of the data indicated that the teacher's use of traditional assessment activities was more dominant than alternative assessment activities although the latter was strongly emphasized by the curriculum. Moreover, implementation of alternative assessment activities was not in line with what the curriculum stated. Decisions of policy makers, lack of instructional time, exclusion of the curriculum by the teacher, inadequate pedagogical content knowledge and insufficient teacher training on assessment were found to be the elements that might have negatively affected the alignment negatively. Possible actions that may support a higher level of alignment were discussed.