We present evidence on the impact on students´ math and reading scores of one of the largest deployments of a One Laptop Per Child program and the only one implemented at a national scale: Plan Ceibal in Uruguay. We have the exact date of laptop delivery for every student in the sample. This gives us the ability to use a continuous treatment, where days of exposure are used as a treatment intensity measure. We use a difference-in difference strategy including fixed effects at the individual level and identify the effect of the program net of potential heterogeneity in the rate schools located in Montevideo and the rest of Uruguay gain improvements on student’s achievement over time in the absence of the OLPC program. Our results suggest that in the first two years of its implementation the program had no effects on math and reading scores.