The aim of this study is to investigate the extent of understanding of the basic concepts included in the Islamic Religion Text by the fourth grade students in the Province of Muscat through answering the following research questions: 1- What are the basic concepts included in the Islamic Religion Text for the basic fourth grade students? 2- What is the extent of comprehension of the basic concepts included in the Islamic Religion Text by the basic fourth grade students in terms of gender, type of education, knowledge levels and the areas of the subject? The targeted population of the study was the students of the basic fourth grade in government and private schools of Muscat Province-for- the academic year (2003/2004). The total size of the population was 3970 male and female students. The researcher has analyzed the text contents to extract the basic concepts and prepare an objective instrument, which was further validated. The validity factor was 82%. The most important results of this study were: 1- Understanding of the basic concepts included in the Islamic Religion Text by the basic fourth grade students was educationally acceptable. 2- There were no statistically significant differences in the average scores of the students in acquiring the basic concepts in the whole instrumrnt. 3- There were statistically significant differences in the average scores of the students between the public and the private schools in understanding the basic concepts at (0.05) in favor of the private schools students. 4- The lack of statistically significant difference at (0.05) in the average scores of the students between the public and private schools is attributed to the gender variable. 5. The statistically significant difference in the average scores of the students at (0.05) is attributed to the knowledge level variable (remembrance, comprehension, application) in favor of comprehension. 6- The statistically significant differences in the average scores of the students at (0.05) are attributed to the change in the subject areas (Quraan, Hadeeth, Ageeda, Fiqh, Seera, Akhlaqe) in favor of Akhlaq (morals). The study has presented many recommendation, the most important of which is the importance of diversifying teaching methodologies of the concepts to include; concepts maps, extrapolation, measurement, and others.