In the number to position task, several studies have shown that typically developing children shift from a biased (logarithmic) to an accurate (linear) mapping of symbolic digits onto a spatial position on a line. The initial pattern of overestimation of small numbers and the underestimation of larger numbers is compensated by means of age and education. Children with mathematical disability seem to show less accuracy in placing numbers on the line and their mapping tends to be more biased than linear. Here we evaluate to what extent this hypothesis holds for a sample of Italian children who have received a formal diagnosis of developmental dyscalculia (DD). Ten children with DD (M age-months = 123, SD = 25) and ten typically developing (TD) children (M age-months = 121, SD = 23), matched for age and gender, completed two number to position tasks (intervals: 0-100, 0-1000). For the interval 0-100, children with DD obtained a mapping in an intermediate stage between logarithmic and linear whereas the TD group reached a linear mapping. For the interval 0-1000, children with DD exhibited a logarithmic mapping whereas TD children had a linear mapping. These results highlight the presence of basic numerical deficit in children with DD.