The paper develops a formula for inbreeding probabilities in the multi-locus case, this formula being analogous to that given by Malecot for single-locus chromosomes. A detailed example provides a comparison between the present approach and that by Malecot and it is found that the two methods produce slightly different results. This slight difference is then shown to be due to certain paths in pedigrees which seem to have been overlooked by Malecot. An indication of calculations necessary for higher-locus cases concludes the paper.