Writing is considered the most challenging skill by most Vietnamese students learning English, especially among non-English major students at colleges and universities. These students encounter various kinds of problems in their writing process, from generating ideas to revising their own texts. While many studies in the literature focus on exploring how to help students write better using different techniques, few studies have been conducted to explore the kinds of errors that Vietnamese students usually make in their written work and their preferences for the kind of feedback that teachers provide. Since the knowledge of students’ preferences of teacher’s feedback types is useful in helping teachers to teach writing more effectively, it is important to conduct research on this matter. The current study was conducted with 60 non-English major students in a college in Vietnam. Data were collected from a survey and in-depth interviews. The findings revealed that morphological errors, lexical errors, syntactic errors and mechanical errors were four most common types of errors that students made in their written work. Their preferences of teachers’ feedback for each type discovered from individual interviews shed some light on what teachers should do when revising students’ writing products.