This article describes experiments of using the short message services (SMS) of mobile telephone systems in efforts to reduce nonresponse in mail surveys. SMS may provide a new tool for increasing the efficiency of the data collection process in self-administered surveys. Such experiments were feasible in Finland because nearly everyone in the country has a mobile phone. In addition, nearly all mobile phones are listed in a publicly accessible database that contains all telephone numbers. The tests focused on potential differences between an experimental group (those sent an SMS reminder) and a control group (those sent the standard postcard reminder). Statistically significant differences were found between these respondent groups. The results were very encouraging, indicating that SMS reminders lowered the nonresponse rate more efficiently than traditional postcard reminders did. Besides practical questions concerning the use of SMS reminders, this article also discusses the related advantages and disadvantages.