Writing samples of 97 students in remedial writing classes were analyzed to determine error patterns in writing mechanics and the predominance of specific errors. Students were grouped according to individual student profiles and error patterns which indicated additional similarities and differences among individuals. Analysis indicated that most students shared the error patterns of spelling and punctuation, although the patterns were crosscut by other categories. Significant findings were: (1) students with proportionally more errors in their compositions were those with more highly differentiated problems of error; (2) only four percent of the students showed very high error count in all areas of writing mechanics; (3) spelling was the most severe generalized problem of mechanics; and (4) students showed marked variation in their writing skills profiles. Individualized instruction would help the student overcome obvious difficulties and concentrate attention on clearly defined individual needs. (CWM)