A study was conducted to compare the adaptive ability of three indigenous goat breeds (Osmanabadi, Malabari, and Salem Black) to heat stress. The primary objective of the study was to assess the thermo-tolerant ability of these breeds to heat stress based on the changes in their blood biochemical response and aldosterone concentration. Thirty six-ten months to one year old female goats were randomly allocated into six groups of six animals each as OCON (n=6; Osmanabadi control), OHS (n=6; Osmanabadi heat stress), MCON (n=6; Malabari control), MHS (n=6; Malabari heat stress), SCON (n=6; Salem Black control) and SHS (n=6; Salem Black heat stress). The OCON, MCON, and SCON animals were maintained in the shed while OHS, MHS, and SHS animals were exposed to summer heat stress between 10:00 h to 16:00 h. All the animals had access to ad-libitum feed and water. The duration of the study was 45 days. The results indicated that breed differences (P < 0.01) were established for the levels of plasma glucose, total protein, albumin, and globulin. However, heat stress treatment did not influence these variables. Further, heat stress significantly increased (P < 0.05) plasma cholesterol only in the MHS group. Besides, albumin/globulin (A/G) ratio, plasma urea, and plasma urea nitrogen (PUN) did not show any significant variation both among and within the breed for the treatment. However, plasma triglyceride was significantly lower (P < 0.05) in both OHS and SHS groups as compared to their respective control groups. Further, aspartate aminotransferase (AST) showed significant variation for the breed (P < 0.05) as well as treatment (P < 0.05) with a higher concentration in the OHS group. Among the breeds, heat stress induced lower (P < 0.05) plasma aldosterone was established only in the MHS group. Thus, it can be concluded from the results that the Malabari breed which was well known for its survival in a harsh environment in its native tract could not adapt well to the new locality with a much lower magnitude of heat stress. However, Salem Black breed could exhibit superior adaptability to the new agro-ecological zone which was comparable to that of local Osmanabadi breed.