This paper presents the most relevant results of a study in which opinions of the teachers in the area of Fresno (Central California, USA) about the effects of the integration of mobile devices into the teaching-learning process. Among other objectives, this study has tried to analyze the influence of mobile learning over three very important learning factors: affective-emotional (motivation), ethic-social (social skills) and the cognitive one (cognitive skills). In order to carry out this study, a descriptive methodological approach was adopted, using the survey technique as the most adequate method to collect teachers´ opinions in a relatively fast and precise way. Obtained results show a widespread agreement among teachers about the pedagogical potential of mobile devices as a tool to improve learning quality. In general terms, conclusions suggest an improvement in the students’ interest on educational tasks, an increase during study activities, a better collaborative work, as well as an improvement of creativity and information acquisition