This research aimed to determine classroom teachers\' beliefs about the integration mathematics and science. A random sample which consisted of (216) classroom teachers from the center for open education were asked to answer (70) items - scale related to principles of integrating mathematics and science, benefits of integrating mathematics and science, demands and problems of integrating mathematics and science , skills of integrating mathematics and science , and teachers\' attitudes towards integrating mathematics and science. The results showed that the mean score of teachers\' beliefs about the integrated mathematics and science was below the hypothetical mean (60%). The results showed that there was no significant statistical difference at the level of) α = 0.05) between the mean scores of teachers\' beliefs on the integrated mathematics and science due to the teachers\' gender, the teachers\' experience and the teachers\' qualification.