Parameters of a Middle Pleistocene human population such as the expected length of the female reproductive period (E(Y)), the expected interbirth interval (E(X)), the survival rate (tau) for females after the expected reproductive period, the rate (phi(2)) of women who, given that they reach first birth, do not survive to the end of the expected reproductive period, and the female infant plus juvenile mortality rate (phi(1)) have been assessed from a probabilistic standpoint provided that such a population were stationary. The hominid sample studied, the Sima de los Huesos (SH) cave site, Sierra de Atapuerca (Spain), is the most exhaustive human fossil sample currently available. Results suggest that the Atapuerca (SH) sample can derive from a stationary population. Further, in the case that the expected reproductive period ends between 37 and 40 yr of age, then 24 less, similarE(Y) less, similar27 yr, E(X)=3 yr, 0.224</=tau</=0.246,0.49<phi(2)</=0.754 and 0</=phi(1)<0.264. When, however, the end of the expected reproductive period occurs after 40 yr of age, it turns out that 24 less, similarE(Y) less, similar30 yr, E(X)=3 yr, 0.204</=tau</=0.246, 0.74<phi(2)</=0.754 and 0</=phi(1)<0.056.