This exploratory study examines a subset of mobile phone use, the compulsive use of short message service (SMS) text messaging. A measure of SMS use, the SMS Problem Use Diagnostic Questionnaire (SMS-PUDQ), was developed and found to possess acceptable reliability and validity when compared to other measures such as self-reports of time spent using SMS and scores on a survey of problem mobile phone use. Implications for the field of addiction research, technological and behavioral addictions in particular, are discussed, and directions for future research are suggested.