The present study aimed to investigate the effect of using problem-centered learning strategy on learning achievement and motivation of fourth-grade students toward learning mathematics. The researcher used the semi-experimental method, where the number of members of the study sample was (59) students from the fourth grade in Attalaei school of basic education (1-4) in the governorate of Buraimi. The sample was divided into two groups, one experimental (30) students studied using the learning strategy centered on the problem. The controlled group consisted of (29) students studied in the usual method. Pre and post- tests based on the syllabus of math have been applied to the study sample, in addition to the measurement of motivation towards learning mathematics. To investigate the hypotheses of the study, the data were analyzed using T-test of two independent groups to determine the differences between the two groups and Pearson correlation coefficient. The study revealed the following results: • There were statistically significant differences at the level of significant (α=0.05) between the average grades of the fourth grade students in the post-test of achievement in mathematics and the post measurement of motivation toward learning mathematics, in favor of the experimental group which studied using the problem- centered learning strategy. • There were positive correlation between students' grades in the achievement test and the measurement of motivation toward learning mathematics for the experimental group studied using the problem-centered learning strategy. In the light of the results, the study recommended to utilize the use of problem-centered learning in teaching mathematics. In addition reformulating the content of mathematics, and develop it in the way that helps teachers to use modern strategies such as problem-centered learning. Finally, The study suggested that similar studies should be carried out at different levels of study and in other topic in mathematics.