This study aimed to evaluate the extent to which text simplification can improve reading comprehension and fluency for students between the ages of 7 and 9. Text simplification was performed at three levels (lexical, syntactic, discourse) for both literary and scientific texts. A computerized reading tool (eBook for iPad) was developed to have an on-line measure of reading fluency and comprehension. A cohort of 170 2nd grade students participated in the experiment. The students read 20 original or simplified texts by themselves and at their own pace. The texts were followed by 5 comprehension questions with 3 possible answers. Preliminary results suggest that text simplification improved both reading fluency and comprehension for literary texts but had no effect on scientific texts. Students understood the simplified literary texts better than both the original and simplified scientific texts. The same children will be followed for3 years to determine which factors predict reading comprehension and fluency at the end of primary school. The integration of normative data will allow us to have a computer tool that is capable of tracking reading comprehension and fluency over time.