In January 2012 the Cook County Department of Public Health (CCDPH)investigated an outbreak of norovirus among customers of Bob Chinn's Crab House located in Wheeling, Illinois. Illness onsets ranged from January 2, 2012 through January 13, 2012. In total, 196 persons were counted as outbreak associated cases. Three customers and 4 restaurant food handlers were laboratory confirmed with norovirus. Two cases were hospitalized. Forty cases sought medical care at a hospital emergency department or a health care provider. Analysis of case control data showed that multiple foods were statistically associated with illness. Coleslaw had the highest odds ratio (10.99, 95% CI 5:59, 21.60, p<0.001).