Abstract: Background and Objective: The heat stress of quail plays an important role in feed utilization, blood profile, growth performance and its influence economic loss. Supplemented of volatile oil garlic is one the efforts to avoid the negative impact of heat stress. This study was conducted to investigate the potential of garlic powder in improving feed utilization, some parameters of blood biochemistry and performance. Materials and Methods: A total of 400 laying quails was used in this experiment. Animal samples were obtained at 6 week of age randomly assigned to 4 groups of treatment. Each group of treatment involved 10 replicates with 10 quails each (100 laying quails per group). All of the groups were provided basal diet and supplemented with volatile oil of garlic 0 (control), 0.75, 1.50 and 2.25 mL L–1 drinking water for group of D0, D1, D2 and D3, respectively. All of the groups were exposed heat stress under 33-35°C. Faces and eggs ware collected and also measured feed consumption to determined feed utilization. Blood sample was collected and centrifuged to separate plasma. The plasma was used for determination of concentration of blood biochemistry by spectrophotometer method, based on BIOLABO kit. Data were analyzed by one-way ANOVA using SAS. Results: Based on the results of this study, there was significant effect (p<0.05) supplementation of volatile oil garlic on the feed utilization between D0 and D1, D2, D3. Commonly, supplemented of volatile oil garlic showed significantly affected (p<0.05) on the blood biochemical and performance, however did not significantly affected (p>0.05) on the glucose and low density lipoprotein (LDL) . The administration of 2.25 mL L–1 drinking water was a optimum level for increasing feed utilization, improving profile of blood biochemistry and rising performance. Conclusion: The result in this study indicated that bioactive compound in volatile oil can be improved feed utilization, metabolism rate and quail production by administration 2.25 mL L–1 in drinking water.