In this study, psychometric properties of the test of the three-mathematical minds (M3) were investigated. The M3 test was developed based on a multidimensional conception of giftedness to identify mathematically talented students. Participants included 291 middle-school students. Data analysis indicated that the M3 had a 0.73 coefficient as a consistency of scores. Exploratory factor analysis yielded three separate factors explaining 55% of the total variance; however, one-factor solution seems to best fit the data. The convergent validity analysis showed that M3 scores had medium to high-medium correlations with teachers' ratings of students' mathematical ability and students' ratings of their own ability and their liking of mathematics. The findings provide partial evidence for the validity of M3 test scores for the identification of mathematically gifted students. (Contains 7 tables and 3 figures.)