Recent trends in the study of written texts reflect a growing interest in interaction between readers and writers. Several studies have focused on metadiscourse as an important interactive feature that is believed to facilitate the reading process. While several authors have studied metadiscourse from the descriptive and contrastive perspectives, there is a lack of experimental work on this topic. This paper describes exploratory classroom research with a group of Italian university students to gain further insight into the effect of metadiscourse on ESP reading comprehension. Two groups of students read selected extracts from two versions of the same text differing according to quantity and type of metadiscourse. Each group then took a reading comprehension test and their mean scores were compared. The findings suggest that a more pronounced use of metadiscourse may be associated with improved comprehension in some cases. A post-reading questionnaire showed that students had substantially no awareness of metadiscourse. The results provide useful indications for further research and also highlight the need for targeted instruction on metadiscourse in ESP reading courses.