The effects of the oral supplementation of probiotics on the performance and intestinal histo-morphology of the duodenal, jejunal, and ileal mucosa, comparing with two different genetic lines (purebred Large White or crossbred Large White x Landrace) of suckling piglets were evaluated between 2 and 19 days of age. In total, 276 piglets were distributed according to a completely randomized experimental design in a 2 x 3 factorial arrangement. with four replicates each. Treatments consisted of two genetic lines (130 purebred Large White and 146 crossbred Large White x Landrace piglets). two different probiotic products (probiotic bacteria or a combination of . yeast and probiotic bacteria), and a control (basal diet with no addition). Probiotics increased the average daily weight gain (P=0.02), independently of . genetic line, but did not influence (P>0 10) average daily feed intake. Crossbred piglets presented higher average daily feed intake (P=0.03) than purebreds. The incidence of diarrhea was not significantly different (P>0.10) among the treatments. Intestinal histo-morphometric parameters were not influenced by genetic lines (P>0.10). However, the piglets fed with the probiotic products exhibited higher duodenal villi compared with the control (P=0.01). In conclusion, piglets that received oral probiotics improved intestinal health and average daily weight gain, independent of' the genetic lines. Higher duodenal villus were measured in P2 and P3 (450.37 mu m and 435.62 mu m, respectively) compared with the control group P1 (309.25 mu m; P=0.01). Higher average daily weight gain was obtained in P2 and P3 (259.55 g and 250.50 g, respectively) compared with P1 (221.9g: P=0.02).