This study examines the effects of antitrust prosecution on prices charged by firms indicted for price fixing. In a survey of 25 cases filed between 1973 and 1984, prices are found to gradually rise by about 7 percent over the 4 years following an indictment. However, the severity of penalties is negatively correlated with prices. These two findings suggest either that penalties are too lenient or that prosecution is too broad, penalizing economically efficient conspiracies along with those that are inefficient.