The aim of this study was to determine the situation of pre-service primary school teachers' use of Turkish on the internet. The research was conducted on 100 students studying at the department of Primary School Education of Mustafa Kemal University. The research was descriptive. Data of the study was obtained from the students' conversations in Facebook in the preceding month. Percentages were applied for the analysis of statistical operations. As a result of the study, the students' mistakes made while using Turkish on the internet were categorized into three groups which were phonetic features, vocabulary use, and spelling. Consequently, it was revealed that 62% of pre-service primary school teachers used undotted letters instead of Turkish letters, 83% of them did not use vowels, 58% of them made phone repetitions in stress-aimed words, and 50% of them wrote time affixes improperly.