A phylogeny of extant penguins (18 forms) was estimated on the basis of 70 integumentary and breeding characters. Integumentary characters included structure and color of bill and legs, and plumage of adult, immature, and downy chick. Breeding characters included eggs, nesting, and sociability of immatures. Gavia was placed at the root, and 11 species of representative procellariiform groups completed the outgroup. A heuristic parsimony analysis under implied character weights was performed. Ingroup resolution was complete. The analysis recovered monophyly of Sphenisciformes and all the traditional genera. The ingroup topology was ((Eudyptula Spheniscus) (Aptenodytes (Pygoscelis (Megadyptes Eudyptes)))). Two suprageneric groups, (Eudyptula Spheniscus) and (Megadyptes Eudyptes), were well supported. Additional analyses under equal weights resulted in a consensus topology that differed only in the internal resolution of Spheniscus. Integumentary and breeding characters performed optimally at the ordinal and generic levels, and also provided resolution and varying degrees of support at the supra- and intrageneric levels.