This research entitled “An Error Analysis of Prepositions in Descriptive Texts Made by Students of Madrasah Aliyah Nurul Huda Dowora in Tidore” is an attempt to classify, analyze and descripe the errors in the use of prepositions in descriptive texts. It was carried out at Madrasah Aliyah Nurul Huda Dowora in Tidore. The method used in this research is descriptive. Aarts and Aarts' (1982) concept is used to explain the types of prepositions. To find out the kinds of error in prepositions made by the students. Jha (1991) theory is used to explain the types errors in prepositiosn made by the students.. The data of the research were taken from the students' writing assignment. The results of this research show that there are three kinds of preposition errors made by the students. First, the omission of preposition-the students drop a preposition in a sentence where it is obligatory. Second, the insertion of preposition-the students add a preposition in a sentence where it is not necessary. Third, the selection of incorrect preposition ed in a sentence.