Telemarketer identity verification uses an application executing in a smartphone or tablet device. When a call is received, the application takes the number and attempts to verify whether it is associated with a known telemarketer. If so, the application queries the telemarketing service for additional data about the call. The service responds with additional details, for example, the subject of the intended call. The user is then provided an notification that an incoming call is being received. At this point, the user knows that the call is from a telemarketer, that the telemarketer has been verified, and the nature of the call. This information is then output to the user, e.g., visually, aurally, physically, or some combination thereof. The visual representation may include a “decline” button that may be selected by the user. If the call is declined, the client application may then notify the telemarketing service to that effect.