Pertussis is a highly infectious, vaccine-preventable respiratory illness. With the advent of a vaccine, case numbers fell in the United States from a high of 265,269 in 19341 to a low of 1,010 cases in 1976, but then resurged to 25,827 in 2004. During 2004-2008, the average was 18,161 cases per year.2- 3 Close contacts of persons with pertussis are at increased risk for developing infection and are recommended to receive preventive antibiotics4 for two reasons: (1) the illness can be debilitating, with cough lasting several weeks and sometimes being severe enough to cause urinary incontinence, rib fracture, or other complications; and (2) the illness can be fatal in infants; it caused an average of 17 deaths each year during 2002-2006.3 During pertussis outbreaks, the resources needed to identify and treat contacts can strain local public health resources.5 The Douglas County Health Department (DCHD) in Omaha, Nebraska, responded to a school-based pertussis outbreak with 26 cases occurring in late 2008. To assess the costs incurred by a local health department responding to such an outbreak, DCHD and CDC evaluated the total resources used by DCHD. This report describes the results of that analysis, which indicated that (1) staff members reported 1,032 person-hours spent responding to the outbreak, and (2) the total cost of outbreak response, including overhead, labor, travel, and other costs, was $52,131 (measured in 2008 U.S. dollars). The majority of costs (59%) occurred during an intensive 10-day period, when most of the contact tracing and prophylaxis recommendations were made. The elevated incidence of pertussis and the burden of response placed on health departments warrants exploring the impact of alternative response and chemoprophylaxis strategies.