The authors, since 1985, have used 587 Madreporic Coral grafts as bone substitute in a total of 183 patients, among them in 80 cases for repair of cranial base bone defects. They report their long-term results. Partial resorption to about 40% of the initial volume occurred in almost all cases within 8 to 10 months, with complete resorption after about one year. 20% of the coral blocks moved spontaneously or split into pieces, but could easily be withdrawn rhinoscopically through the nostrils. No CSF leakage was noticed afterwards. The local infection rate was only 4%, always close to the basal coral graft. This is lower than the infection rate after using autologous bone harvested from the inner table of the bone flap (20%). Infections were cured by removal of the coral graft. Despite the mentioned draw backs, Madreporic Coral graft implants can be recommended as bone substitute in cranial base surgery: 1. The material simplifies the surgical procedure; 2. Harvesting of autologous bone is no longer necessary; 3. Transmission of infections like AIDS, Hepatitis C or Creutzfeld-Jacob-disease can be avoided with certainty.