The objective of this work was to study the morphometric characterization of Santa Inês sheep to aid the conservation genetics of this breed in different micro-regions of the State of Piauí. For this, morphometric measurements have been collected in sheep from different micro-regions of the state of Piauí. The body measurements, collected were withers height, hip height, chest circumference, body length and ear length. The averages of the measures obtained in each micro-region were evaluated and by the use of the principal component analysis, helped by the SAS PROC PRINCOMP, it was possible to group populations based on similarity measures. The groups were formed relying on a cluster analysis by Ward method. Considering the analyzes, phenotypic diversity was found in Santa Ines sheep reared in the state of Piaui; being formed by a group of larger animals, located in the region of Floriano, Médio Parnaíba Piauiense, Teresina and Campo Maior; another group of animals of intermediate size, but with greater body length and girth circumference and small ears, located in the microregion of São Raimundo Nonato, another group with intermediate size and big ears and the last group of smaller animals located in the region of the Litoral Piauiense and Valença. The measures that contributed mostly for the principal component analysis were measures of hip height, withers height and body length
characterization; conservation genetics; morphometry; multivariate analysis