The PPAR- gene encodes for at least 7 unique transcripts due to alternative splicing of five exons in the -untranslated region (UTR). The translated region is encoded by exons 1–6, which are identical in all isoforms. This study investigated the role of the -UTR in regulating the efficiency with which the message is translated to protein. A coupled in vitro transcription-translation assay demonstrated that PPAR-1, -2, and -5 are efficiently translated, whereas PPAR-4 and -7 are poorly translated. An in vivo reporter gene assay using each -UTR upstream of the firefly luciferase gene showed that the -UTRs for PPAR-1, -2, and -4 enhanced translation, whereas the -UTRs for PPAR-5 and -7 inhibited translation. Models of RNA secondary structure, obtained by the mfold software, were used to explain the mechanism of regulation by each -UTR. In general, it was found that the translational efficiency was inversely correlated with the stability of the mRNA secondary structure, the presence of base-pairing in the consensus Kozak sequence, the number of start codons in the -UTR, and the length of the -UTR. A better understanding of posttranscriptional regulation of translation will allow modulation of protein levels without altering transcription.