Reported here are four fractured femoral components from a consecutive series of 200 total hip reconstructions. All four had been placed in patients who weighed ninety-one kilograms or more and who were more than 1.8 meters tall. In each patient, roentgenograms made prior to the time of failure of the prosthesis revealed roentgenographic lucency, which was interpreted as cement failure. Metallurgical examination revealed fatigue failure and some abnormality in each prosthetic stem. Review of all 200 total hip replacements suggested that there was failure to position the prosthesis in strong valgus in there four hips and in thirty others. In the four failures, the contributing influences of large size of patients, inadequate valgus positioning of the prosthesis, inadequate support by cement, and metallurgical inadequacies of the prosthesis used are discussed.