Over 755 million adults worldwide are unable to read and write in any language. Yet the widespread introduction of information and communication technology offers new opportunities to provide standardized distance education to underserved illiterate populations in both developed and developing countries. Using data from a randomized experiment of an innovative mobile phone-based adult education program (Cell-Ed) in Los Angeles, we find that the Cell-Ed program significantly increased students’ basic and broad reading scores, equivalent to a 2-4 year increase in reading levels over a four-month period. The program also increased participants’ self-esteem by 7 percent as compared with the comparison group. These results are robust to correcting for non-random attrition using a variety of non-parametric methods, including using the phase-in design to tighten the Lee bounds. Our results suggest that there is great scope for using information technology as a means of improving educational skills for illiterate adults.