This study was conducted to explore and analyze the most common essay writing errors among Saudi female learners at the departments of English, Majmaa'h University, Kingdom of Saudi Arabia. Therefore, the aim has been to identify those difficulties from an error analysis standpoint and identify the sources underlying them. An analysis of a written corpus of forty students' written essays was thoroughly conducted. Types of errors were categorized, and the factors that contributed to them were analyzed. "The participants were English majors in their third year of study" enrolled in an advanced writing course during the first term pertinent to the academic year 2018-2019. "Three essays were given to each participant to write about two to four pages" using the narrative, descriptive, and compare/contrast organization. A writing difficulties questionnaire was further employed. "The findings showed that the most frequent types of errors made by the participants were": punctuation errors forming the most troublesome area, followed by spelling errors, preposition errors, article errors, wrong verb tense, wrong word form respectively. The findings suggested that writing in English as a foreign language is quite challenging for students. Interlingual and intralingual transfer was found to be the source underlying the most common errors.