The present study was aimed at identifying laminar lesions and leukocyte infiltration in hoof laminar tissue of horses with colic syndrome and its correlation with the total leukocyte count before death. Six healthy horses were used as control group (CG), and eighteen horses with lethal gastrointestinal disease were divided into two groups: leukopenic group (LG) with seven leukopenic horses, and non-leukopenic group (NLG) with 11 horses with total leukocyte count within reference range for the species. Leukocyte infiltration was examined by immunohistochemistry. Laminar lesions were observed in both LG and NLG, with no differences in severity between them. LG showed increase of the leukocyte infiltration in the hoof laminar tissue, when compared to CG and NLG. Horses with severe colic syndrome (LG and NLG) developed intense laminar lesions without clinical signs of laminitis, with increased leukocyte infiltration. However, the LG demonstrated an even higher increase of leukocyte infiltration compared to both CG and NLG.Post-Graduation in Veterinary Sciences, Federal University of Paraná, Campus of Curitiba. Rua dos Funcionários, 1540, 80035-050, Curitiba, Paraná - BrazilPost-Graduation in Veterinary Sciences, Federal University of Paraná, Campus of Curitiba. Rua dos Funcionários, 1540, 80035-050, Curitiba, Paraná - BrazilPost Graduation in Veterinary Surgery, Júlio de Mesquita Filho São Paulo State University - UNESP (Jaboticabal campus). Via de Acesso Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo - BrazilDepartament of Veterinary Medicine, Federal University of Paraná, Campus of Curitiba. Rua dos Funcionários, 1540, 80035-050, Curitiba, Paraná - BrazilPost Graduation in Veterinary Surgery, Júlio de Mesquita Filho São Paulo State University - UNESP (Jaboticabal campus). Via de Acesso Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo - Brazil