Sub-zero saline solutions were evaluated for the improvement of chilling efficiency and product quality of broiler carcasses. In this study, four experiments were conducted to chill broiler carcasses using different saline solutions and chilling temperatures in the Meat Processing Center at California Polytechnic State University (Cal Poly, San Luis Obispo, CA) or in the processing plant at Foster Farms (Livingston, CA). In Experiment I, three salt concentrations and solution temperatures (0% NaCl/0.5°C, 4% NaCl/-2.41°C, and 8% NaCl/-5.08°C) were used to chill carcasses. The fillets in brine chilling at sub-zero temperatures showed lower shear forces than the fillets in 0% NaCl control solution. In Experiment II, three salt concentrations (0% NaCl/0.5°C, 4% NaCl/-2.41°C, and 8% NaCl/-5.08°C) were used to chill carcasses with/without pre-chilling in 0% NaCl/0.5ºC or 0% NaCl/14°C. Fillets from the carcasses in 4% NaCl/-2.41°C significantly improved tenderness (P < 0.05), with no significant difference observed for the shear force of 8% NaCl/-5.08°C, regardless of pre-chilling. In Experiment III, four salt concentrations (0% NaCl/0.5°C, 1% NaCl/-0.6°C, 2% NaCl/-1.2°C, and 3% NaCl/-1.8°C) were used to chill carcasses. The shear force of fillets decreased as the salt content increased and chilling temperature decreased from 0%NaCl/0.5°C to 3%NaCl/-1.8°C, with the lowest shear force observed in 3% NaCl brine at -1.8°C (P < 0.05). The chilling time (90 min) of 3% NaCl was reduced by 25 min (or 22%) compared to water control (115 min), with an intermediate reduction (13 - 17%) v seen for other NaCl solutions (95 – 100 min). Breast fillets showed no significant difference in chilling yield, pH, R-value, and sarcomere length for raw meats as well as in cooking yield and salt content for cooked fillets across all treatments (P > 0.05). In Experiment IV, three salt concentrations (0% NaCl/0.5°C, 3% NaCl/-1.8°C, and 4% NaCl/-2.41°C) were used to chill carcasses. The chilling time (55 min) of 4% NaCl was reduced by 35 min (or 39%) compared to the time (90 min) of water control, with an intermediate reduction (11%) seen for 3% NaCl solution. Control fillets in 0% NaCl showed a higher shear force than the fillets in sub-zero brine chilling (P < 0.05). Based on these results, broiler carcasses chilled in 4% NaCl/-2.41°C appears to be ideal to improve both chilling efficiency and meat tenderness compared to the carcasses chilled in 0% NaCl/0.5°C.