Various errors come out during writing as it is a highly complicated skill and requires higher-order thinking skills to activate the cognitive processes. Determining these errors is crucial for eliminating them. Mostly preferred way for determining them is performing an Error Analysis (EA). Hence, employing a screening model, the study aimed to reveal types, categories, and sources of errors in Turkish EFL students’ writings as well as to explore potential differences in error frequencies based on their departments and genders by performing an EA. The data obtained from the research were analyzed through document analysis. The sample of the study included 42 students studying at ELT and ELL departments of a state university in Türkiye. All of them were in English preparatory classes and at B2 level. They were asked to write an essay in 150-250 words about one of the given topics. The error analysis revealed a total of 962 errors in Turkish EFL students’ writings. The errors were gathered under three types: grammatical, semantical, and mechanical errors. Among these, grammatical errors were the most prevalent, encompassing a wide range of categories including verb/tense errors, article errors, preposition errors, and others. Semantical errors, involving word choice, coherence, and ambiguity, followed next in frequency. Mechanical errors namely spelling, capitalization, punctuation, and contractions, were also prominent. The current study sought to explore whether there were statistically significant differences in error frequencies between students majoring in English Language Teaching (ELT) and English Language and Literature (ELL), as well as between female and male students. The analysis demonstrated that there were statistically no significant differences between the error frequencies of ELT and ELL students. On the other hand, a statistically significant difference was observed between error frequencies of female and male students. Female students produced less errors compared to the male ones.