The current study was designed to trace changes in the relationship between non-word reading and irregular word reading on the one hand, and between phonological awareness and non-word reading on the other, through a follow-up study of a group of individuals with Down syndrome. Twelve individuals with Down syndrome, whose data were originally reported in Roch and Jarrold (2008), were seen four years later, and were given the same tasks as in the previous study evaluating phonological awareness, non-word reading and irregular word reading. After four years, an improvement was observed in all the skills of interest. Furthermore, the pattern of relationships among the three skills was observed to change considerably across the four year period. At the first time point, a weak association between non-word and irregular word reading was found, but there was a strong association between these two measures at the second time point. In contrast, a strong relationship was found at Time 1 between non-word reading and phonological awareness, which became weaker at Time 2. Longitudinal associations between the three skills were also examined in order to explain this changing pattern of associations. The results indicated that the ability to decode non-words plays a marginal role on later irregular word reading. In contrast, irregular word reading is a longitudinal predictor of later non-word reading. Phonological awareness was not longitudinally related to non-word reading. The results indicate that developing word knowledge can facilitate later non-word reading in Down syndrome, perhaps by a process of reading by visual analogy to known lexical items. Learning outcomes: Readers will be able to (a) explain the development of word reading, non-word reading and phonological awareness in Down syndrome; (b) explain the longitudinal changes in the relationships among the three skills; (c) explain the relevance for education of the influence of word reading for the improvement in non-word reading. (Contains 3 tables.)