The objective of this research is to study the methods available to calculate the cohesive energy of tonic crystals and to apply these methods to the calculation of the cohesive energy of the rutile form of stoichiometrlc titanium dioxide. Rutile was selected because a search of the literature indicated that the cohesive energy of rutile has not been calculated and the cohesive energy is required as one of the initlal steps in the investigation of dislocation energies in rutile