We implement an original method based on the estimation of a production function, to investigate how the decrease in the cost of computers has affected the marginal cost of firms, their aggregate labor demand and their skill structure. Following a panel of 5000 French firms between 1994 and 1997, we find strong but heterogenous effects across firms. For the median firm, we evaluate the elasticity of the marginal cost to the price of computers at 0.05, the elasticity of aggregate labor to the same price at 0.07 and the elasticity of the ratio of unskilled to skilled labor at 0.26.