The objective was to evaluate the effect of postmortem aging on marination performance of early-deboned chicken breast fillets (pectoralis major) with different color lightness. Effects of marination on muscle shear force were also determined. Early-deboned (2 h postmortem) broiler butterfly fillets were visually selected based on their color lightness (pale, normal, and dark) from a commercial plant. The individual butterfly fillets were separated into left and right fillets. One of them was used for 6-h marination treatment and the other for 24-h marination treatment. Samples were marinated in a vacuum tumbler (-0.6 atm, 16 rpm, 20 min) with 20% wt/wt marinade yielding 0.75% NaCl and 0.45% phosphate in the final product. The effect of aging on salt-induced water gain by breast muscle was also measured using the swelling/centrifuging method. Marinade uptake, marinade retention, raw product yield, and cooked product yield were determined after tumbling, following storage for 24 and 48 h after marination and after cooking. Salt-induced water gain was greater (P < 0.05) in nonmarinated fillets at 24 h postmortem compared with 6 h postmortem. Compared with unmarinated fillets, marination enhanced finished product yield significantly (P < 0.05) regardless of postmortem aging and color lightness. Marinade retention and product yield were different (P < 0.05) in fillets categorized by L* (lightness) values. There were no differences (P > 0.05) between 2 postmortem aging times for marinade uptake, overall product yield, cooking loss, final cooked product yield, or meat shear force regardless of initial fillet L* values. However, marinade retention of 6-h samples was significantly better than 24-h samples (P < 0.05). These results demonstrate that with a targeted 15% marinade uptake, postmortem aging of 2-h deboned fillets before marination does not affect marinade uptake and product yield, but significantly affects marinade retention by boneless skinless chicken breast.