Introduction: Non-attendance and delay for vaccination schedules remains a big challenge to healthcare workers.  Among the frequently mentioned reasons for missed vaccination in children is the lack of communication between child caretakers and health workers. This necessitates developing an appropriate and uninterrupted vaccine delivery strategy with more focus on demand side interventions like forgetfulness.Objectives: This paper aimed to develop and test an automated mobile text message reminder system in the local context.Methods: Before development of the system, interview and document reviews were used for requirement gathering. This system is developed using iterative development process through phases of requirement analysis, design, development, testing and refinement. Front end application was developed using Java technologies while back end applications were developed with Oracle database. Finally, pilot testing was done on 30 participants before actual implementation.Results: The automated system has been developed based on requirements. The text message reminder system has two components: 1. Web based application for client registration and automatic reminder scheduling; 2.SMS application for automatic SMS text messaging. In the final testing, all the messages (100%) were delivered to the piloted mothers. Message speeds for each individual client ranged on average from 5 second to 30 seconds.Conclusion: Text message reminder system has been developed for routine childhood immunization program in Ethiopian context. Text message interventions should be carefully developed, tested and refined before implementation to ensure they are written in the most appropriate way for their target population.