In this article I examine the inherent characteristics of teachers' work, as a form of intellectual activity, in relation to the changes that this work is undergoing under the neoliberal mode of capitalist accumulation, that can be identified as teachers' "proletarianisation". I emphasize that the work of teachers, as a creative and essentially innovative intellectual activity, is about results that can be appropriated through peoples' consciousness and cannot be quantitatively measured or evaluated by using some standard, time-performance criteria. In the article it is underlined that teachers' work, as a form of intellectual activity, is not limited to conventional labour time, draws resources (information, knowledge, creative ideas) from all moments of social life and, therefore, extends to all moments in the life of its bearers. In connection with that it involves the activation of the teachers' entire personality and consequently the success of this work largely depends on the overall development of teachers' personalities. I also reflect on some specific structural aspects of teachers' work, such as a) the knowledge transmission, b) the development of the students' cognitive-cultural abilities and c) the cultivation of learning interest and social attitudes. By examining the phenomenon of teachers' "proletarianisation" and "alienation", I focus on the essential contradiction between teachers' work and the dominant law of capital accumulation as well as the neoliberal policies imposed on education. At the end I distinguish some crucial fields of teachers' struggle against proletarianisation and alienation.