Intramuscular fat (IMF) content and composition, particularly the oleic fatty acid content (OL), are major quality characteristics of pork fresh and dry-cured products. They are known to be related to nutritional, manufacturing and organoleptic properties, as well as to human health. It is known that IMF content is under genetic control but little evidence is available for IMF composition, namely OL. There are very few estimates in the literature regarding genetic parameters for OL (Suzuki et al., 2006) and, besides, most of them are based on small data sets from experiments designed for other purposes (Ntawubizi et al., 2010; Sellier et al., 2010). However, genetic parameters associated to IMF and OL (i.e. heritability and genetic correlations with other relevant traits) are needed for developing selection criteria and optimum breeding strategies and programmes. IMF content is usually expressed in percent of dry or wet matter and OL in percent of total fatty acids in IMF. However, all research done in this field was not aware of the compositional nature of these data (Aitchison, 1986). The purpose of the present contribution is to compare results from standard linear with compositional data analyses for IMF and OL. Analyses were compared in terms of genetic parameter estimates, selection efficiency, and predictive capacity.