EFL teacher training for pre-service teachers plays a vital role in second language teacher education (SLTE). In Thailand, pre-service EFL teacher training benefits in helping student-teachers gain confidence before going to their practicum. This study investigates the effects of the pre-service EFL teacher training in a university in Thailand. The pre-service teachers' perceptions towards the EFL training were also examined. Participants were 30 pre-service teachers currently studying in English Learning Management Program in the university at the research site. Research method applied training program evaluation (Owen & Rogers, 1999), and a 24-hour EFL training program was implemented. An experienced trainer in EFL was invited to provide the EFL training during the whole training course. Data collection gained was from: 1) an evaluation form, 2) a questionnaire, and 3) a student reflection sheet. Data analysis employed percentage, means, and S.D. for quantitative whereas grounded theory (Strauss & Corbin, 1999) was applied for qualitative data. Three major findings revealed that: 1) the effects of the preservice EFL teacher training was very high; 2) the participants showed changes in all areas of EFL knowledge and experience provided after the training; and 3) the participants viewed five factors which included training contents, knowledge and experience, training activities, training process, and the trainer that affected the training. However, the findings indicated that the critical problem of the study was time limitation of the training course. This study has shed light on the significant role of EFL training for pre-service EFL teachers before their practicum as the findings showed positive change in their motivation and attitude for their teaching practice.