Abstract: Background and Objective: Group size has a great effect on goat physiology but hard to predict if it acts as a stress factor. The aim of the present study was to show that what extent the number of goats/group affects the hormonal balance. Materials and Methods: In the present study, 12 adult female goats were divided into two groups, large and small size group. Some stress indicators as cortisol and prolactin were measured through blood samples to evaluate the effect of group size on goat physiology and to ensure the stress effect of the group size if present. SPSS was used to analyze the data using t-test. Results: The final result revealed that there was no significant effect of the group size on goat hormonal balance, despite the difference in hormonal concentrations between the two groups, as in the last month of the study the p-value for the difference in cortisol concentrations between the two groups was (p = 0.1) and (p = 0.6) for the difference in prolactin concentrations between the two groups. Conclusion: It was concluded that by increasing the number of goats/group, affected on physiology of the goats through elevations of some hormones like prolactin but this effect was not significant.