Teachers' attitudes and teacher training are two of the main factors to integrate a new technology or a new methodology in the classroom. In that sense, although there is a lot of literature about using video games in education and about their educational possibilities, teachers' attitudes can influence the application of video games as an educational resource. For that reason, in this paper we are going to focus on teacher attitudes and teacher training, in particularly, of in-service primary school teachers. Also, we are going to focus on collaborative learning with video games, topic that is explained in the paper. Regarding specific objectives, they are the followings: (1) to know the attitudes of primary school teachers (in-service) towards collaborative learning with video games, (2) to know if they have received previous educational training about video games in education and (3) to know if there is any statistically significant difference due to the fact of having received training or not about this topic. To reach these objectives and to show the results, this paper has been divided into four parts. The first part, introduction, deals with literature about video games and education. The second part is about the method of our study, including the instrument and the process to collect data. The third part shows the results of the study and the fourth part includes the conclusions of our research. Finally, in summary, we can say that primary school teachers have a positive attitude towards collaborative learning with video games. However, most of them say that they have not received teacher training about video games and education and this fact is influencing their attitudes, so teachers who have received training about that have better attitudes that teacher who have not received this kind of training.