This study was undertaken to evaluate Saanen and Azul goats' adaptability to the Brazilian Middle-North region, based on adaptation indexes (Iberia, Benezra and Rainsby tests). A totall of seven and four females, respectively, of each group were used in two tests and four collections were performed during the rainy and dry periods of 2005 year. A completely randomized experimental design in a 2 x 2 (2 groups x 2 period) factorial treatment combination was used. Significant difference between groups (Saanen = 97.65 and Azul = 94.31) was observed for heat-tolerance coefficient (Iberia) during the dry period (P<.05). Significant differences between groups (P<0.05) were also observed for adaptability, coefficient 1 (Benezra) for both rainy (Saanen = 5.13 and Azul = 3.26) and dry periods (Saanen = 5.86 and Azul = 2.87). Based on Rainsby test, Azul goats returned to rest temperature in both periods. During the dry period 100 minutes were not enough for Saanen goats return to rest temperature. Azul goats showed higher adaptability to environment conditions of the Brazilian Middle-North region.