This study investigated the influence of culture and discussion participation on rhetorical patterns in the reflective essays of 238 Korean and 196 American 4th-graders. Results showed significant differences between Korean children's essays and American children's essays in types of reasons, uses of argument elements, and uses of rhetorical forms; but no difference in organizational structure. The effects of free-flowing collaborative discussions on children's essays interacted with culture. After participating in a series of discussions, Korean children made larger gains than American children in use of elements of argumentative discourse. (Contains 8 tables.)