Writing is one of the important language skills because it is used in students' daily activities. Students should actively think while writing to turn their thoughts and ideas into written communication in a continuous and useful process. Some of the problems faced by grade VIII students of MTs Zainul Hasan Genggong Pajarakan Probolinggo in writing English stem from the structural differences between Indonesian and English, as well as their lack of knowledge about how to write well. In addition, the students' lack of interest in learning English. The last point is that students only practice based on their textbooks, giving them little opportunity to express their ideas in writing or speaking in English. The purpose of this study was to determine the extent of knowledge about writing English students in the school environment in Islamic boarding schools, by knowing what types of errors and the frequency of each type of error made by students in writing descriptive texts in class VIII MTs Zainul Hasan Genggong Pajarakan Probolinggo. For the research design, this study used a quantitative descriptive method. The subjects in this study were 25 students of class VIII IT MTs Zainul Hasan Genggong Pajarakan Probolinggo, selected based on interviews with English teachers. The data collection technique used was a writing test with one of these themes ((1) Describing oneself, (2) Describing favorite place, (3) Describing favourite idol, (4) Describing hobby, or (5) Describing friend) in a composition consisting of 100-250 words and within 45 minutes. There are 4 categories of grammatical errors, omission, addition, misformation and misordering. The research procedure consisted of six steps; organizing and preparing data for analysis, reading all of the data, beginning a detailed analysis with the coding process, using the coding process, interpreting and meaning the data, and drawing conclusions. Based on the results of data analysis, there are four types of grammatical errors in writing descriptive text made by grade VIII Of MTs Zainul Hasan Genggong Pajarakan Probolinggo, including omission, misformation, addition, and misordering totaling 181 errors. The occurrences of omission error is 83 or (45.8%). The occurrences of misformation error is 71 or (39.2%) (the occurrence misformation error in article were 8 items (11,2%), 6 items (8,4) of preposition, 27 items (38,02) of verb, 8 items (11,2%) of noun and 22 items (30,9%) of pronoun). The occurrences of addition error is 23 or (12.7%). The occurrences of misordering is 4 or (2.20%). Thus most common errors made by students in writing descriptive text is omission.   Keywords: Analysis Errors, Descriptive Text, writing.