The present work was carried out to evaluate the effectiveness of the probiotic Pediococcus acidi-lactici in alleviating the toxicity of aflatoxin B₁ (AFB₁) in male New-Zealand white rabbits. Twenty four male New Zealand white rabbits, 800-1000 g body weight were used in the present work. Rabbits were randomly divided into four equal groups: Group (1) served as a control group. Group (2) was fed on crushed pellet diet mixed with the probiotic Pediococcus acidilactici at a dose of 100g/ton feed for six successive weeks. Group (3) was fed on crushed pellet diet artificially contaminated with 60 ug of AFB₁/kg of diet for six successive weeks while Group (4) was fed on crushed pellet diet mixed with the probiotic Pediococcus acidilactici (the same dose mentioned in G2) and artificially contaminated with 60 ug of AFB₁/kg of diet for six successive weeks. Evaluations were made for chromosomal aberrations, hemato-biochemical parameters, immunological changes as well as histopathological alterations. Our results showed that AFB₁, possesses a mutagenic effect. It sig- nificantly increases the frequency of chromosomal aberrations. AFB, induced significant de- crease in the total leukocytic count associated with lympopenia. Serum biochemical analysis revealed significant elevation in ALT, AST, GGT activities and BUN concentration with a marked decline in total proteins, albumin and globulins concentration. Significant decrease was recorded in the phagocytic percent and phagocytic index of neutrophils of aflatoxicated rabbits. Supplementation of the probiotic Pediococcus acidilactici to the aflatoxicated diet in- hibited the mutagenic effect of   AFB₁, as it sig-nificantly decreased the frequency of chromoso- mal aberrations. Furthermore, Pediococcus acidilactici improved the hemato-biochemical altera- tions and nullified the phagocytic percent and phagocytic index of neutrophils of aflatoxicated rabbits.