We sampled lice from 2 species of Neotropical thrushes, Turdus assimilis, the white-throated robin, and T. grayi, the clay-colored robin, to document the prevalence, intensity, abundance, and species richness on each host. Sampling was conducted in 1999 in the Coto Brus Valley of southern Costa Rica using a modified dust-ruffling technique. The prevalence of lice was high—lice were recovered from 93% (n = 14) of T. grayi and 86% (n = 22) of T. assimilis individuals sampled. Observed prevalence and generic-level louse diversity were similar to those reported for T. migratorius, the American robin, in Newfoundland, Canada, although T. assimilis and T. grayi tended to have higher proportions of lice belonging to the suborder Amblycera. Turdus grayi hosted marginally more louse species (mean = 1.6, SD = 0.8) and had marginally higher louse abundance (mean = 33.9, SD = 27.9) than T. assimilis (mean = 1.1, SD = 0.6 and mean = 16.5, SD = 17.3, respectively), although T. grayi and T. assimilis are closely related and similar in size. Distributions of lice on the 2 species were aggregated, indicating substantial individual variation in the abundance of lice supported.