Purpose and significance: According to the DPM, problems can be categorized according to whether the problem, method or solution is known by the presenter and/or the solver. The DPM includes six problem types. But it is a continuum model so more types can be added to the Matrix. The purpose of this study was to search new problem possibilities to integrate into the DPM and to investigate the psychometric properties of the revised DPM. Method: Participants included 519 students from 10 schools. Of the total sample, 248 were 6th graders (141 female; 107 male) and 271 were 7th graders (154 female; 117 male). In the first stage of the research study, the DPM was reviewed and a new problem type was added to the DPM. Next, a measurement instrument was developed according to the revised DPM (r-DPM). The instrument was adminis-tered to the participants to investigate its psychometric properties. Results: Reliability coefficient was found to be .75. For the validity of the r-DPM, expert’s views were used, correlations between problem types were examined and grade discrimination was investigated. Positive and statistically significant correlations were found between the problem types. Parallel to previous research, the more distant two problem types are from each other, the lower the correlation between them, and the closer the problem types are to each other, the larger the correlations between them, which is a fact that provides evidence for the validity of the Matrix. Seventh graders had higher scores than the sixth graders on the in-strument.Discussion and Conclusions: The DISCOVER Problem Matrix (DPM) can be used as a theoretical framework to develop instruments for measuring problem solving skills related to different intellectual abilities as well as educational activities and tasks to develop these skills. It has been used in the assessment and education practices in gifted education. The current study extended previous studies about the DPM and provided additional evidences related to its reliability and validity. Results of the study showed that the DPM has sufficient convergent and divergent validity because the more distant two problem types are from each other, the low-er the correlation between them (discriminant validity), and the closer the problem types are to each other, the larger the correlations between them (convergent validity). These findings are parallel to those obtained by Sak and Maker (2005). The new problem type added to the Matrix also had a good fit with the structure of Matrix. Furthermore, evidence also was obtained in terms of the Matrix’s discriminant validity. That is, 7th graders scored higher than the 6th graders on the Matrix-based instrument. This study provided research evidence about the reliability and validity of the revised DISCOVER Matrix. Because, it’s a problem continuum model, more problem types should be added to the Model.