Reading comprehension and fluency are crucial for successful academic learning and achievement. Yet, a rather large percentage of children still have enormous difficulties in understanding a written text at the end of primary school. In this context, the aim of our study was to investigate whether text simplification, a process of reducing text complexity while keeping its meaning unchanged, can improve reading fluency and comprehension for children learning to read. Furthermore, we were interested in finding out whether some readers would benefit more than others from text simplification as a function of their cognitive and language profile. To address these issues, we developed an iBook application for iPads, which allowed us to present normal and simplified versions of informative and narrative texts to 165 children in grade 2. Reading fluency was measured for each sentence, and text comprehension was measured for each text using multiple-choice questions. The results showed that both reading fluency and reading comprehension were significantly better for simplified than for normal texts. Results showed that poor readers and children with weaker cognitive skills (nonverbal intelligence, memory) benefitted to a greater extent from simplification than good readers and children with somewhat stronger cognitive skills.