This study aimed at evaluating the narrative performance reports for the basic fourth grade students in the subject of mathematics for academic year 2010/2011. The study aimed at determining the proportion of the availability of narrative performance reports for the basic fourth grade students, the consistency of teachers' estimates in the narrative performance reports, the degree and the direction of the correlation between teachers' estimates of narrative performance reports and their grades in the achievement test that prepared in the researcher, and the degree and the direction of the correlation between teachers' estimates of narrative performance reports and their grades in the end of the academic year. The sample of the study included a random sample of 559 narrative performance reports for basic fourth grade, divided into three provinces: Muscat, Buraime and South Batinah. The researcher used Two instruments: The first instrument was achievement test in mathematics for basic fourth grade. The validity of the instrument was obtained through (10) referees. The reliability calculated using Cronbach's Alpha coefficient, and the second instrument was a checklist to identify the standers included in the narrative performance reports for basic fourth grade. The validity of it was obtained through (10) referees. The reliability obtained by calculating the percentage agreement between the researcher's analysis and an external analyst's analysis. The results of the study indicated that 1) Lack of a number of important standers in writing narrative performance reports for basic fourth grade such as a description of each criterion-reference. 2)There is consistency in estimates of the parameters in narrative performance reports within one teacher's estimates. 3)There is statistically significant positive correlation between estimates of descriptive performance reports for students and their grades estimated by the parameter at the end of the school year. 4) There is a statistically significant positive correlation between estimates of descriptive performance reports for students and their grades in achievement test prepared by the researcher, According to the results of the study, the researcher set some suggestions and recommendations.