The present study aimed to (1) Investigate the comparability of PISA 2006 and TIMSS 2007 (2) Analyze the similarities and differences of frameworks of PISA 2006 and TIMSS 2007. In accordance with the purpose of the study, content analysis was done. Content analyses showed that content of two international studies were similar to each other in some extent. The competencies and cognitive skills were also similar on surface whereas the base of the competencies and cognitive skills were different. In order to find similarities and differences, the items assessing the similar cognitive skills were selected for PISA and TIMSS. The analysis of the items in terms of the percentage of Turkish students’ correct answers demonstrated that while identifying scientific issues in PISA and knowing in TIMSS were not similar, explaining phenomena scientifically in PISA and applying in TIMSS and using scientific evidence in PISA and reasoning in TIMSS were similar.