  A detailed model is constructed for the calculation of electron capture rates
of some fp-shell nuclei for situations prevailing in pre-supernova and collapse
phases of the evolution of the core of massive stars leading to supernova
explosion. The model uses explicitly the Gamow-Teller strength function
obtained through (n,p) reaction studies wherever available. The rates include
contribution from the excited states of the mother as well as from the resonant
states in equilibrium with the back reaction i.e. the beta decay of the
daughter nucleus. Comparisons are made with the shell model results and the
earlier calculations by Aufderheide et al. and Fuller, Fowler and Newman. For
the nuclei $^{56}$Fe, $^{55}$Mn and $^{60}$Ni with negative Q-values one
observes large contribution from the excited states.
