Five separate formulations of ground beef patties were processed to represent differences in animal maturity, muscle pH, fat content and processing of hot vs cold boned beef. Patties were cooked on electric griddles to internal temperatures (thickest portion) of either 68.3 or 71.1degreeC before making visual and instrumental assessment of color. High pH ( > 6.2) muscle (whether obtained 48 h postmortem or through hot processing) produced more red, uncooked color, while patties made from younger age (apprx 36 months) cows (regardless of fat content) appeared more well-done. Patties processed from high pH (not hot processed) muscle had the highest saturation index and highest CIE a* values (71.1degreeC only), but still required the longest cooking times to reach final internal temperatures. Reductions in CIE a* values between 68.3 and 71.1degreeC temperatures were observed only for patties made from hot processed muscle. This may be related to the decrease in pH that occurred during the early stages of cooking for this formulation. Differences in color between the two internal temperatures were minimal with patties cooked to 68.3degreeC possessing higher CIE b*, higher saturation index and lower hue angle values (p ltoreq 0.01). Inconsistent relationships between cooked color and internal temperature in cooked patties may result when broad differences exist in muscle pH and animal maturity between ground beef formulations.