The aim of this study is to explore the beliefs of female science teachers in the second cycle of basic education about the scientific argumentation and its relation to their classroom practices. It also focuses on examining the influence of teaching experience on these beliefs. The sample of the study consists of (117) female science teachers in the second cycle of basic education in the Muscat governate for the 2013/2014 year. The belief scale was applied on female science teachers about the argumentation. Additionally, an observation form was conducted on a sample of (20) female teachers. In order to achieve the aim of the study, the researcher used two instruments: First, the argumentation beliefs scale which consisted of (31) items distrusted on three domains. Second, an observation form which consisted of (13) items distrusted on three domains too. The validity of the scale and the observation form was examined by a panel of arbitrators. The reliability of the beliefs scale was examined by using cronbach's alpha for internal consistency on a sample not included in the real sample. The coefficient was (0.93). The reliability of observation form was applied by tow in depended researchers on a sample not included in the real sample too, and Pearson correlation coefficient was (0.95). This indicates that both instruments are appropriate for the aims of the study. The results of the study highlight the below: • There are a strong argumentation beliefs. The mean of the responses to the scale was (4.24/5.00) There is no statically significant differences at (a=0.05) on the mean of the beliefs attributed to teaching experience There is a weak classroom practice about the argumentation. The mean for that was (1.52/3.00( There is no statically significant differences at (a=0.05) on the practice about the argumentation attributed to teaching experience •There is no statistical relation at (a=0.05) between the beliefs of female science teachers about the argumentation and their classroom practices In the light of the above results, the study highlights the importance of putting more concern to train teachers pre and in services about applying the argumentation, and this can be achieved through training courses and workshops. The study also emphasizes the role of educational supervising in directing teachers to use and pay more attention to the argumentation. Finally the study recommends to conduct more research about the argumentation in the future.