The present study examined the development of mathematics skills of Kosovar primary school children in terms of their gender, living area, socio-economic status, and achievement level. A special emphasis was placed on longitudinal investigations of the development of mathematics skills in children with learning difficulties in mathematics over a 2-year and 4-month period. Participants were 553 fourth-graders, 85 of whom identified with mathematical learning difficulties were classified into two subgroups: children with low mathematics achievement and children with limited mathematics ability. Results have shown that there were no gender differences in mathematics achievement. Children's living areas as well as their socio-economic status were observed to have a substantial impact on math performance. The performance level of limited math ability children was lower as compared to low math achieving children on all of the measures assessing math outcomes and reading comprehension. Findings indicate that a majority of the limited math ability group members still met the cutoff criterion after more than 2 years of school attendance.