This article investigates the possibility of a contagion effect in each of fourteen Latin American republics from 1949 through 1963. Using a data set drawn from the Hispanic American Report, riot frequencies are compared with the Poisson and contagious Poisson distributions. The authors find evidence of contagion in six countries, and suggest that contagion as a concept encompasses a variety of behavioral processes. In addition, the authors attempt to reconcile contagion studies with more traditional studies of political violence.