The objective of this study was to evaluate whether the use of a diet rich in oleic acid could have an effect on daily weight gain, backfat and loin muscle (Longissimus thoracis) depth. One hundred and ninety-two barrows and gilts, from two genotypes were fed a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic acid (HO with 43% C18:1, Greedy-Grass OLIVA®). The pigs were housed in 16 pens in groups of 12 according to their sex, diet and genotype. From 75 days of age every three weeks, the pigs were weighed and the backfat and loin muscle depth were ultrasonically recorded (PIGLOG®). The inclusion of the dietary fat had no significant effect on the growth variables nor on the backfat and loin muscle depth measurements taken. However, the barrows resulted in higher live weight and backfat compared to the gilts at the end of the trial. Conversely, the gilts showed higher loin depth. Moreover, York-sired pigs were heavier than Pietrain-sired pigs during the whole trial and showed higher backfat at the last two measurements. Pietrain-sired pigs had higher loin muscle depth at the last measurements. The results of the present study suggest that the addition of a dietary fat into diets aiming at modifying the meat fatty acid profile has no detrimental effects on performance variables, or on backfat and loin muscle growth and thus, no negative economic impact for producers.