Punctuation is important for English language learners especially in writing sentence or paragraph. Punctuation helps readers understand the message conveyed. The goal of this research was to identify the students’ ability in using punctuation marks and the most mistake made by the students in using punctuation mark. In this research, the researcher used quantitative research for the research design. This research was conducted at English Education Department at Universitas Muhammadiyah Yogyakarta. The participants of this research were EED student batch 2014 and the researcher took 60 students of 160 from the total of the students. The researcher used test for the instrument of the research. The test consisted of 20 unpunctuated sentences and the students had to complete the sentence with the punctuation marks correctly. There are two findings the researcher found in this research .The first finding is about EED students’ ability to use punctuation mark. There were no students (0%) who got score A in the category of excellent. There were 8 (13%) students who got B or in the category of good, 9 (15%) students who C or satisfactory, 30 (50%) students who got D or unsatisfactory, and 13 (22%) students who got E or poor (<39). The score of D and E comprises 72% EED UMY students batch 2014 who were not able to use punctuation mark correctly. According to the finding, the students need to increase the ability in using punctuation mark correctly. The second finding revealed that the most common mistake in using punctuation made by the EED students was in using quotation mark. The finding showed that quotation mark is the most common mistake made by EED UMY students.