A comprehensive writer identification test was designed and administered to a group of professional document examiners and a control group of nonprofessionals. The professional group consisted of seven document examiners from the FBI, while the control group consisted of 10 graduate students in the areas of engineering and business. A data base of 86 documents created by 20 writers was used for the test. Each participant was given the same 86 documents and was instructed to sort them into separate piles. Each pile was to include documents created by the same writer. Professional document examiners from the FBI performed significantly better than control group members, indicating that handwriting identification expertise exists. The findings call into question the conclusions of previous studies in this area. Methods used by professional document examiners are discussed. 16 references and 5 tables