Increased psychological stress, engendered in the remaining animals as each animal was taken and killed, sequentially, from a pen of four animals, decreased M. longissimus dorsi (LD) glycogen concentrations at 30 min (initial) and4·5 h postmortem and initial (12 min postmortem) M. semitendinosus (ST) pH values. Increasing stress, with order of slaughter, was associated with increased initial temperatures in both muscles. Stunned animals had lower initial temperatures in LD and ST than unstunned animals. pH values at 4·5 and 6sd5 h postmortem in the LD and at 6·5 h in the ST were greater in muscles from stunned sheep than in those from unstunned sheep. LD glycogen concentrations at 4·5 h postmortem were greater in animals receiving less feed; an effect only in part due to the faster cooling rate of their lighter, less fat carcases. Initial ST glycogen concentrations were approximately half those of initial LD glycogen concentrations.