Discourse markers, as words or phrases, play a significant role in promoting coherent segments of discourse. They facilitate text interpretation and were key attributes in linking sentences, rendering the text coherent. This corpus-based research work was conducted to identify and compare the categories and functions of discourse markers (DMs) in the corpora of the American vs. Iranian newspaper. To do so, a corpus of 30 editorial articles was extracted from New York Times and 30 editorials from Iran Daily. The framework proposed by Fraser (1999) was employed to classify the detected categories of discourse markers (DMs) in three functions including contrastive, elaborative, and inferential. The obtained results from the descriptive statistics and Chi-Square test revealed that the American newspaper with total number of 168 DMs was found to be superior to Iranian newspaper with total frequency of 98 in terms of occurrence of DMs. More specifically, the findings indicated that the frequency of contrastive DM in the American newspaper was higher than the occurrence of this DM in the Iranian newspaper. Further, the frequency of both elaborative and inferential DMs in the New York Times editorials were considerably higher compared to the editorials extracted from Iran Daily newspaper.