Mathematically gifted and talented students are different from other students when it comes to their needs and requirements. Therefore, it is necessary to develop and apply programs suitable for their readiness, interest and learning profiles. For this purpose, the aim of this study is to investigate the effect of a differentiated mathematics instruction program developed for gifted and talented students on their mathematical attitudes. In the study, "Mathematics Attitude Scale" developed by Baykul (1990) was used to measure the mathematics attitude of students in Turkey diagnosed as gifted and talented. The study was designed as a controlled pre-test post-test experimental study. The study sample consisted of twenty-four fifth grade gifted students, 12 children in the experimental and 12 in the control group. The statistical analysis of the data collected in the study was made using SPSS 16.0 and it was found that a differentiated mathematics teaching program prepared by the researcher increased the mathematics attitude of gifted and talented students.