We randomly offer to workers in Chile personalized versus generalized information about their pension savings and forecasted pension income. Personalized information increased the probability and amounts of voluntary contributions after one year without crowding-out other forms of savings. Personalization appears to be very important: individuals who overestimated their pension at the time of the intervention saved more. Thus, a person’s inability to understand how the pension system affects them may partially explain low pension savings. Despite the significant response to the intervention, its temporary nature and size suggest that information should be combined with other elements to increase its efficiency.