Species flocks, large clades that have evolved from a common ancestor within a limited geographic range such as an ancient lake or isolated islands, provide splendid opportunities to study many aspects of evolution. Lake Baikal, which is at least 16 MY old and contains fully oxygenated depths of up to 1650m, harbors a unique fauna that includes several spectacular endemic species flocks (sponges, planarians, at least 3 groups of gastropods and, finally, amphipods). There are at least 250 described species of endemic Baikal amphipods that represent two independent invasions into Baikal. Baikal amphipods possess extreme morphological and ecological diversity. Morphologically, they include miniature and giant (up to 12cm) species, highly-armored, spiny species strikingly resembling unrelated marine forms and the unique planktonic amphipod Macrohectopus branickii. Ecologically, they range from typical generalist omnivorous/detritus-feeding species to highly specialized active predators, abyssal scavengers, plankton feeders, parasites or commensals of spongers and parasites of other amphipods. Thus, wide ecological diversification and high species richness make the adaptive radiation of Lake Baikal amphipods an excellent model system for adaptive research. Here we report transcriptomes of 64 species of lake Baikal amphipods.