This study aims to determine the level of understanding the nature of science for the teachers of science in (6 - 10) classes in the basic education along with its relation to their practices in the classrooms. It was also concerned with some variables such as gender and experience. The study sample consisted of 87 science teachers among whom were 49 males and 38 females in the basic education schools in the year 2005/2006. To achieve the study objectives the researcher designed two tools: 1. A measure for understanding the nature of science consisted of 36 statements divided into 6 categories: (nature of scientific knowledge, experimental basis for scientific knowledge, the role of creativity in the production of scientific knowledge, the cultural and social impacts on the scientific knowledge, observation and inference, and theories and tays relationship). 2. Observation sheet, which consisted of 29 statements, categorized according the classification of the 6 categories stated earlier. The credibility of the research instruments was judged by 24 judges. In addition, the reliability index was calculated through two pilot administrations of the instruments with a group outside the target sample with two week interval between the two administrations. The value of person correlation between the results of the tow pilot tests was .81. In addition, the reliability of the observation instruments was calculated, resulting in a value of .86. These values show the suitability of the two instruments. The results of the present study can be summarized as follows: 1. The performance of grades 5 - 10 science teachers in Basic Education was significantly lower than the accepted rate of 80%. 2. There was a significant difference at p=<.05 in the means of male and female teachers in favor of the latter both in the whole scale and also in the first and second dimensions. 3. There was no significant difference between male and female teachers based on teaching experience those bellows and above five years. 4. The teachers' application and adaptation of the nature of science in their classrooms was low. 5. There was no significant difference between male and female teachers in their understanding and application of science. The study recommended according to the results that it is necessary taking care of developing the understanding for the nature of science with the teachers of science through organizing in service workshops that tackles certain subjects. These subjects are as such as: philosophy of science and its history, dimensions of the nature of science, the emphasis on the role of educational supervision on following up the development of understanding the nature of science with the teachers, and finally it also recommended more studies to take place in the nature of science..