Although the number of immunization is covered, it is necessary to optimize them so that all children get immunized. Human-Centered Design (HCD) can be a solution to optimize immunization coverage. The aim of the Training of Trainers (ToT) activities is to increase the capacity of health workers is to increase their understanding and ability regarding Human Centered Design (HCD) as a method of solving the problem of not achieving immunization coverage in Central Java. The training four consecutive days, with interactive learning designs including lecture methods, facilitation, discussions, quick investigation practices, and presentations held in Banyumas Regency. The number of trainees consists of 30 participants from 5 districts (Brebes, Banjarnegara, Cilacap, Banyumas, Pemalang, and Tegal). The media used in this training are power points, modules, textbooks, pocketbooks, videos, and other tools for quick investigation. Evaluation does by giving pretest and posttest every day. Based on the results of the pretest and posttest, there was an increase in participants' knowledge about HCD material. Participants can carry out quick investigation practices, make prototypes and present them according to the HCD Steps. This service concludes that there is an increase in knowledge and ability to carry out HCD so that participants are ready to become HCD training trainers. It is necessary to carry out HCD training for health workers, cadres, and other community elements to solve the problem of immunization in the community.