The purposes of this study were to investigate English essay writing strategies used and English essay writing difficulties encountered by English major students at School of Humanities, University of the Thai Chamber of Commerce, to compare English essay writing strategies used and difficulties in writing English essays encountered by high and low English proficiency students, and to compare difficulties in writing English essays encountered by students with different background.The data were gathered from 272 fourth year English major students of academic year 2005. The subjects passed two writing courses emphasizing on paragraph and essay writing. A questionnaire was used to collect data. Percentage, Means, Standard Deviation and t-test were used for data analysis.The major findings are as follows: firstly, the students practiced most in gathering information for the prewriting stage by using the Internet and preparing to write essays by setting the main idea. Regarding strategies for writing essays, the student wrote introduction by using facts and statistics, wrote the topic sentence as the first sentence in a paragraph, wrote conclusions by summarizing main points, and used transitional words to make ideas coherent. They consulted Thai-English dictionaries, revised and edited essays by checking spelling.Secondly, the students had difficulties the most in getting readers’ attention and using verb tenses.Thirdly, when comparing strategies used in writing English essays between high and low proficiency groups, significant differences at 0.05 were found in all steps in the writing process namely gathering information for essays, planning, writing introduction, body and conclusion of essays, revising and editing.Fourthly, when comparing difficulties encountered by high and low proficiency groups in organizing essays, there were significant differences at 0.05 in both organizing essays and writing essays in English language.Lastly, when comparing difficulties encountered by students with different background, there was a significant difference at 0.05 between male and female students in having no time to revise and edit essays. When comparing students practicing and not practicing English outside classroom, it was found that there were significant differences at 0.05 in both organizing essays and writing essays in English language. Regarding comparison of difficulties encountered by students practicing writing skill and students practicing other skills outside classroom, there were significant differences at 0.05 in both organizing essays and writing essays in English language.