Writing tasks assigned in 162 undergraduate and graduate courses in several disciplines at eight universities were collected. Using a sample of the assignments, key dimensions of difference were identified, and a classification scheme based on those dimensions was developed. Application of the classification scheme provided data on the prevalence of various types of assignments and, for essay tasks, showed the degree to which the assignments were characterized by each of several features. Differences in the kinds of writing tasks assigned in different groups of disciplines were examined.