A system and method for entering USSD codes through an ambiguous text entry interface. The disclosed system may be embedded in mobile devices or other devices having reduced (e.g., 12 key) keypads for text entry. The system receives text entry from users, disambiguates the text entry, and presents the user with descriptors (i.e., representative words, icons, or other visual indicators) that are associated with the entered text and correlated with USSD codes. In response to a user selecting a descriptor, the system retrieves the corresponding USSD code and causes the device to transmit a message to the USSD service. The USSD service receives the message and invokes appropriate processes to respond to the message. In some embodiments, the system presents the list of descriptors representing USSD codes to the user in an order that is related to the probability that the user will select the descriptor.