A study examined (1) developmental differences in the writing of urban students, (2) the syntactic complexity associated with differing modes of written discourse, and (3) the relationship among grade level, mode of discourse, and writing quality. Subjects were approximately 1,200 second, fifth, eighth, and eleventh grade students from large metropolitan schools that had mean scores in total reading below the fiftieth percentile on the Comprehensive Test of Basic Skills and were receiving Elementary and Secondary Education Act funding. The subjects each completed descriptive, argumentative, and narrative writing tasks. Writing samples of 20 randomly chosen subjects at each grade level were selected for analysis. Of these students, approximately 17% were Spanish surnamed, 24% Black, 12% Filipino, 20% Asian, 18% White, and 9% other. The writing samples were scored for total number of words, number of t-units, and quality, holistically determined. Results showed that over the four grades and three discourse modes, the number of words and t-units increased mathematically. For all grades and modes there was a high degree of association between quality and number of words. Eighth and eleventh grade students produced significantly more words per t-unit than did second and fifth grade students, and the three discourse modes did not differ in syntactic complexity as measured by analysis of variance. (FL)