This study employs Douglas Biber's Multi-Dimensional analysis (1988) in order to estimate the degree of similarity and difference between expert and novice academic writing in different disciplines. The Multi-Dimensional analysis was applied to two kinds of corpora: an approximately 700,000-word corpus of L2 students' writing and a 3,700,000-word corpus of professional writing in six sciences (business studies, computer science, economics, history, law, and political science). It was found that there are significant differences in the realisation of Biber's dimensions between the disciplines under consideration, as well as between the learners' and experts' texts. The results show that the novice writing is less narrative, more explicit, more opinionated and less abstract compared to the texts written by professionals.