We review significant empirical studies of the arithmetic abilities of children with dyslexia. These studies suggest that the academic impairments of children with dyslexia are not limited to reading and spelling, but also include aspects of mathematics. A consistent finding across a number of studies is that children with dyslexia have difficulty recalling number facts. The results of the reviewed studies are analysed, both in terms of the weak phonological representations hypothesis, and the triple-code theory of mathematical cognition. It is suggested that the phonological processing deficits of individuals with dyslexia impair aspects of mathematics that rely on the manipulation of verbal codes (e.g. counting speed, number fact recall), whilst other aspects of mathematics that are less reliant on verbal codes (e.g. estimation, subitising) are unimpaired. Suggestions for testing this hypothesis are put forward. (Contains 1 figure.)