Comparative phylogenetic studies of rhesus monkey (Macaca mulatta) and human (Homo sapiens) using G-banding patterns were investigated. Blood samples of rhesus monkeys were examined using lymphocyte culture technique. The results indicate that the number of diploid chromosome of rhesus monkey is 42. The types of autosomes are 18 metacentric and 22 submetacentric chromosomes. The short arm of chromosome pair 13 is a satellite chromosome. The X and Y chromosomes are metacentrics and the smallest metacentric chromosome, respectively. Five chromosome pairs, 5, 12, 13, 19 and X, have the same G-banding patterns as human chromosomes. The short arm of chromosome pair 13 is identical to the chromosome pair 22 and the long arm is identical to the chromosome pair 15 of human. The results infer that the chromosome pairs 15 and 22 of human are derived from the splitting of chromosome pair 13 of rhesus monkey or the chromosome pair 13 of rhesus monkey is derived from the fusion of chromosome pairs 15 and 22 of humans. Additionally, G-banding patterns of 11 chromosome pairs, 1, 3, 6, 7, 8, 9, 10, 11, 14, 17 and 20 of rhesus monkey and humans are similar. The chromosome pair 1 of rhesus monkey and human is pericentrically inverted which is derived from alternate connection of centromeric chromosome. G-banding patterns of 6 chromosome pairs, 2, 4, 15, 16, 18 and Y are different from human chromosomes. The results show that there is a common evolutionary relationship between rhesus monkeys and humans.