Keywords: Conditional sentence, Error Analysis, Writing There are four skills in mastering English, they are listening, speaking, reading, and writing. Conditional sentence is one of grammatical structures in English. It talks about what could happen, what might have happened, and what we wish would happen. The researcher found some English students still making error in using conditional sentence even though they are almost graduate students in IAIN Kediri that already have done with English grammar in early semester. Here, the researcher wanted to know what types of errors do learners have in using conditional sentence and what the possible factors causing the learners errors in using conditional sentence. The researcher used descriptive qualitative method to answer the problem of the research. The subjects of this research were the English Department students 8th semester of State Islamic Institute (IAIN) of Kediri. The researcher used writing test consist of fifteen questions and interview after doing the test about factors causing error in using conditional sentence to the students. To analyse the error, the researcher used surface strategy taxonomy from Dulay’s theory. From the analysis, the researcher found many English Department students grade 8th of State Islamic Institute (IAIN) of Kediri still having error in using conditional sentence. The researcher found 419 error items in using conditional sentence. The most frequent error is misformation items. There are 380 (90%) error items made by 8th semester students. Then, there are 24 (7%) items of omission, 15 (3%) items of addition. The researcher did not find any misordering error in this research. The factors causing them made an error is because they did not remember about the form of the tense, they forgot how the form of the tense is. Students forgot how to use base form, past form, and past participle form in using conditional sentence. Because, when they got conditional sentence in early semester or in high school they did not understand about what the teacher said. The teacher taught too fast, so they did not get it well.

Putri , Winda Isnaini .   (2023). Error Analysis On The Students Ability In Using Conditional Sentence. IAIN Kediri