Eleven Paraguayan strains of Trypanosoma cruzi, from Chagas' disease patients and the bug vectors, were examined by restriction endonuclease analysis of kinetoplast DNA using Hae III, Msp I, Eco RI, HinfI, Taq I and Rsa I. Four schizodeme-profile groups were identified. Group 1 had much simpler profiles than groups 2, 3 and 4 and, although there were homogeneous profiles in the latter three groups, each group could be distinguished from the others. The profiles of group 1 could not be matched with any of the standard strains from Brazil, Chile and Columbia included in the schizodeme comparison. The profiles of groups 3 and 4 shared most features with those standards of the Brazilian Z2 zymodeme.