Intramuscular fat content is a major determinant of meat quality in pigs.Previously, polymorphisms in the adipocyte and heart fatty acid-binding proteingenes, A-FABP and H-FABP, have been significantly associated with geneticvariation of intramuscular fat content in a Duroc pig population. Furthersupport for the role of H-FABP but not for A-FABP was found in a Meishancrossbred population. However, the effect of closely linked genes could not beexcluded in these analyses. To validate the role of A-FABP and H-FABP inintramuscular fat accretion, 153 pigs of a crossbred genotype were evaluated forthe A-FABP and H-FABP polymorphisms, mRNA, and protein expression levels of bothFABP genes and intramuscular fat content in the longissimus lumborum muscle. ForH-FABP, statistical analyses showed significant differences in mRNA but notprotein expression levels between H-FABP HaeIII PCR-RFLP genotype classes.Between these genotype classes, significant differences in intramuscular fatcontent were found within barrows but not in gilts. Moreover, H-FABP mRNA butnot protein expression levels were significantly related to intramuscular fatcontent. For A-FABP genotype classes, no significant differences in mRNA andprotein expression levels were found. However, a significant difference inintramuscular fat content was found within barrows but not in gilts. Inaddition, a significant relationship between A-FABP mRNA but not proteinexpression levels and intramuscular fat content was found. In conclusion,variation of intramuscular fat content could not be explained by differences inA-FABP and H-FABP mRNA and protein expression levels. However, this may be dueto limitations of the assays used and(or) the inappropriateness of the time ofsampling. Finally, results suggest that A-FABP and H-FABP expression aretranslationally rather than transcriptionally regulated.