This study aimed at studying the epistemological beliefs of Yarmouk university students. Particularly, the study aimed at answering these questions: Whether the epistemological beliefs with its various components for male students are similar to female students, or it differs according to the students\' gender? Does the student enrollment in undergraduate and acquisition more of knowledge and experiences affect on his epistemological beliefs? Do the high epistemological beliefs students differ in their achievement of students with low level of epistemological beliefs? Is it possible to predict of the academic achievement of the students through any of the components of epistemological beliefs? The study sample consisted (440) male, female students from undergraduate students in the Faculty of Education at Yarmouk university, during the first semester of the academic year 2009-2010.The results of the study indicated that there were statistical significant differences on knowledge acquisition controlling dimension due to the gender of the student in favor of the female. The results also indicated that the scores of the 3rd and 4th years students on the dimension of knowledge structure and modification were higher than the ones in 1st and 2nd years with statistical significance, and that the scores of the 2nd and 3rd years students on knowledge acquisition controlling dimension were statistically higher than the ones in 1st year. The results also indicated that there were statistical significant differences in to academic achievement between high and low epistemological beliefs groups on the dimensions of the speed in knowledge acquisition, ascertained knowledge, and knowledge acquisition controlling in the favor of high epistemological students. Finally, the results also indicated that the epistemological dimensions that interpreted the proportion of variance in academic achievement level with statistical significant were knowledge acquisition speed and knowledge acquisition controlling dimensions.