The aim of this study was to identify the reflections of performance-based assessment on science process skills, attitudes and retention variables. Study was conducted in Ankara Beytepe Primary School with three seventh grade (one experimental and two control groups) totally 105 students. Science Process Skills Test (SPST) which was developed by Onal (2005) and Attitude towards Science Scale (ATSS) which was taken from literature was used as measurement tools. Performance activities were taken to students and rubrics were developed during the process. After this, SPST and ATSS were applied again to the students for identifying if there was a difference between the groups. Retention test was applied to groups to look for if science process skills were permanent. Research was pre-test post-test control group experimental design. Data were analyzed by t-test and repeated measures of ANOVA. There was a statistical significant difference of variables was found in favor of experimental group.