The aim of this research is to investigate the effect of argumentation-based teaching carried out for environment-energy subjects on argumentation skills of classroom teacher candidates. The research was conducted in accordance with the multiple holistic case study. The study group, which was determined by criterion sampling method, consisted of 44 pre-service teachers studying in the second grade and taking the Environmental Education course. In the argumentation-based teaching process, the scenarios prepared on environmental-energy issues in the socio-scientific structure were used. In the analysis of data, the candidates' individual and grouped arguments were evaluated according to the Toulmin Argument Model; argument average scores were determined according to "Argument Structure Scoring Key", argument levels were determined according to "Argumentation Evaluation Scale". As a result of the research, an increase in the average scores for formation of individual/group, individual and group counter arguments by the classroom teacher candidates from the first activity to the last one was detected and a difference between the mean scores was statistically significant (p < 0.05). The effect size of the difference between the individual and individual counter-argument average scores (Cohen's f) was determined as "wide effect". At the same time, the argument levels progressed from the first week to the last week to the middle and high levels throughout the process. However, it was observed that the progress in the individual counter arguments of the class teacher candidates was not sufficient. As the process progresses, the increase of average scores and argument levels is an indication of the fact that class teacher candidates produce more qualified arguments.