The relationship between children's performance on a standardized achievement battery and compositional writing performance was examined. One hundred thirty-eight writing samples were collected from fourth-grade students. Compositions were scored for both mechanistic and holistic qualities. Four subscores on the Metropolitan Achievement Test were also obtained: word knowledge, reading comprehension, language arts, and spelling. Canonical correlation and multiple regression were used to determine the degree of relationship between these variables. Results indicated that stanadardized test scores have moderate predictive value for children's holistic writing performance. (Characteristics of children with differential performance on writing exercises and standardized tests were also examined, and several implications for teachers were discussed). (Author/MH)