Immunization plays a significant role in the lives of children, by providing strong immune system, and also, fighting against the preventable diseases such as polio, chicken pox, Pneumococcal, rotavirus, HIB, Pertussis, Tetanus and measles. In time past, manual methods have been used in collecting data from mothers and cards were used in reminding mothers about their children immunization. This cards collected can be misplaced by nursing mothers since not all of them will carry the cards wherever they go; but with the development of the repository mobile immunization reminder system (RMIRS) through SMS, the stress of mothers mastering or carrying their children’s immunization card will be minimize to its barest level. Hence, the aim of this work is to develop a repository mobile immunization reminder system for nursing mothers with the use of a modem in order to remind the mothers of their children immunization date. This in turn help in assisting in making life easy and reducing the danger that could be incurred if not immune from the preventable diseases. The system was developed using C# programming language and MS ACCESS database. The database serves as a repository where the records of the child and the mother’s phone number are stored. Also, a standard communication program was customized in developing this work.