Dyslexia is a severe and persistent problem with reading and spelling. Learning to read and spell is crucial for academic learning and functioning in everyday life as an adult. In a series of studies, the role of cognitive skills like memory and attentional skill in treatment of dyslexia was investigated. The results showed that cognitive skills do relate to reading and spelling skills. However, weak cognitive skills appeared not to be related to the amount of progress in reading and spelling skills during reading and spelling training. Moreover, training of weak cognitive skills in students with dyslexia did not prove to be beneficial over and above the reading and spelling training. The result that the specialized reading and spelling training in itself did result in progress of reading and spelling skills, leads to the conclusion that excellent education and training of reading and spelling tasks is of most concern.