Most parthenogenetic animal taxa which have been investigated electrophoretically, cytologically, or with tissue grafting techniques are clonally diverse. I have examined data on multiclonal parthenogenetic populations using ecological diversity measures to elucidate patterns of clonal coexistence. Analysis of a discrete population cage experiment on clones of Drosophila mercatorum revealed monotonic decay of clonal diversity and evenness; however, in a continuous generation cage, clonal diversity appeared to stabilize. Clonal diversity and evenness fluctuated widely over time in several multiclonal populations of Daphnia magna although no clonal extinction was observed. There were few spatial trends in clonal diversity and evenness within parthenogenetic taxa. It is suggested that the degree of clonal differentiation, determined by the mode of clonal origin, is important in determining whether or not selection occurs among sympatric clones