This paper aimed at investigating humor in text-based computer mediated communication (CMC). To this end, 200 turns exchanged by a number of 50 English language teachers on Viber, a messaging application, were randomly selected and analyzed based on Adam's (2012) classification of humor to examine emoticons, punctuations (question mark, exclamation mark, and ellipsis), laughter (textual and acronym), formatting (spelling variations, capital/small letters, and elongation), and explicit markers in the corpus. The findings showed that emoticons outweighed other humor markers while laughter rated the least used marker in the corpus.