Auditors collected information from arrest and court records for offenses that occurred in Cook County in 1996. There were 3,501 arrests, 3,998 court cases, and 5,029 charges with final dispositions in the audit sample. Auditors determined most of the reasons why sample dispositions were not posted to the Computerized Criminal History (CCH) database maintained by the Illinois State Police. They analyzed tracking numbers and statute citations on manual reporting forms and electronic databases to determine if they met information processing requirements. Also, auditors looked at whether law enforcement agencies provided the Clerk of the Circuit Court with information and documents needed to report dispositions. Auditors found that 16.8 percent of arrests in Cook County were not added to the CCH database. Consequently, dispositions in the associated court cases could not be added either. Problems existed with tracking numbers for more than 45 percent of arrests that did not have a disposition in the CCH database. For most of these arrests, the prefix in tracking numbers maintained by the Chicago Police Department and the Circuit Clerk's office differed by one digit. For 24.8 percent of arrests that did not have a disposition in the CCH database, the Circuit Clerk's office submitted inaccurate statute citations and the Illinois State Police's electronic information processor could not accurately read the record. Recommendations to improve the accurate processing of disposition reports are offered. Additional data and information on disposition reporting in Cook County are appended. Tables and figures