All data in the literature on DNA content and nuclear area in the lymphocytes of primates are examined and discussed to assess the possibility of an evaluation of this type of information, along with the cytogenetic data, in the attempt to identify this group in terms of microevolution. 33 species of primates consisting of 4 Lemuroidea, Galago senegalensis, Tarsius syrichta, 11 Cebidae, 10 Cercopithecidae and 6 Pongidae are studied. We used data from man as control. An examination of the general trend shown by these values indicates that all the Lemuroidea, Cebidae and most of the Cercopithecidae have average values not exceeding the standard deviation limits.The highest values are found in Tarsius and in the two Cercocebus species under study; the nuclear DNA content is also high in one Colobine (Nasalis larvatus) and, within the Pongidae, in Pongo pygmaeus. The lowest values belong to the three Hylobatinae under examination (Hylobates lar, Hylobates agilis, Symphalangus syndactylus). The area values, apart from a few exceptions, agree with the DNA values.Statistical analysis demonstrated the existence of significant differences only between genera, not between species, except in the case of specimens from the Cercopithecus genus, where again the values are statistically different from one another.