The Bromeliaceae (Pineapple Family) is an important component of the vascular epiphyte flora of the New World tropics and subtropics. The family, which contains an estimated 2,500 species, is generally considered to be monophyletic, and recent molecular studies indicate that subfamily Tillandsioideae (with the genus Glomeropitcairnia removed) is also monophyletic. In contrast, four of the five remaining genera within the subfamily (Tillandsia, Vriesea, Guzmania, Mezobromelia), which encompass over 800 species, represent artificial groupings based on just one or two characters. Recent morphological and preliminary chloroplast DNA (cpDNA) data suggest that the fifth genus, Catopsis, is monophyletic. The objective of this research is to construct generic level phylogenetic hypotheses for subfamily Tillandsioideae using cpDNA restriction site data obtained from a group of selected, representative species. This molecular phylogeny will be used to evaluate morphological character state changes within Tillandsioideae, as well as form the framework for future phylogenetically based generic level taxonomic revisions within the subfamily.