The production of non-narrative information (descriptive versus expository) across written and oral modes was examined for second-, fourth-, and sixth-grade Greek elementary school students. Written and oral protocols were taken from a total of 240 students at each of 3 grades and evaluated according to: (1) the size of the text produced, measured in the number of idea units produced; and (2) the thematic content of the idea units produced. Results showed a significant increase in the size of written texts produced for both expository and descriptive information between second- and fourth-grade students, and second- and sixth-grade students, but not between fourth- and sixth-grade students. However, such patterns were not revealed for oral protocols. In terms of descriptive information, grade and mode had a significant effect on the total number of idea units produced and the amount of thematically relevant and thematically irrelevant descriptive ideas units produced. In terms of expository information, grade had a significant effect on the total number of expository idea units produced, grade and mode had a significant effect on the amount of thematically relevant expository idea units produced, and the amount of irrelevant expository idea units produced. The lack of significant differences across grades in oral modes may be due to the formal educational programs that stress development and refinement of written skills as opposed to oral skills. Findings also suggest that developmental progression in skills may reach an equilibrium between grades four and six. (Contains six figures of data.) (Author/RS)