The phenomena of peroxisome proliferation in rodent liver has received considerable attention due to its association with hepatocellular carcinoma. Chemicals that cause peroxisome proliferation include several structurally unrelated hypolipidemic drugs, phthalate esters and halogenated solvents. The mechanism by which peroxisome proliferators exert their beneficial (hypolipidemia) as well as their toxic (cancer) effects is still largely unknown. Perfluorodecanoic acid (PFDA) is a potent peroxisome proliferator in rodent liver that resembles other members of this chemical class in many aspects, including its effects on gene expression and fatty acid metabolism. However, there are many dissimilarities between PFDA and hypolipidemic peroxisome proliferators that have not been extensively explored. PFDA is unlike other peroxisome proliferators in parent compound metabolism, hypolipidemia, and tumor promotion. The present review article will discuss what is currently known about PFDA and how it may be utilized to dissect the mechanism of action of an important group of hypolipidemic drug and environmental pollutant, the peroxisome proliferators.