Although many aspects of hummingbird biology have been studied, few recent analyses of higher-level systematic relationships exist. Based on morphology, it has been hypothesized that the Trochilidae includes six major clades. We used starch-gel electrophoresis to construct and test phylogenetic hypotheses for representatives of the six clades, using two species of swifts (Apodidae) as outgroups. Of 45 loci scored, 38 were polymorphic. The average Nei's genetic distance (D) among 14 hummingbird taxa was 0.625; D averaged 1.61 between the swifts and hummingbirds. These distances are large, and are consistent with other nonpasserine groups, suggesting that hummingbird taxa are relatively old. Phylogenetic analyses generally were consistent with the hypothesis that hermits are a sister group to all other trochilines. Within the Trochilinae, two broad groups are recognized, here called trochiline-A and B, which correspond to the morphologically determined 'primitive' and 'advanced' trochiline groups of Zusi and Bentz (1982). Androdon aequatorialis is genetically distinct but generally aligns with the trochiline-A group. Within the trochiline-B group, four radiations hypothesized by Zusi (pers. comm.), here called Bee, Amazilia ('Emeralds'), Andean, and High Andean, were corroborated by our analyses. Our distance analysis suggests a phylogenetic pattern consistent with that derived from Sibley and Ahlquists' (1990) and Bleiweiss et al.'s (1997) DNA-DNA hybridization studies.