The purpose of this work was to collect the main information from the literature about the biotyping of Cryptococcus neoformans. The more up-to date research concerning the epidemiology of cryptococcosis comprising quite a few articles, mainly after the advent of AIDS, was also reviewed. The Cryptococcus neoformans varieties neoformans and gattii are well defined biochemically nowadays chiefly through the C.G.B. medium, according to KWON-CHUNG et al. (1982)24. The isolation of C. neoformans var. gattii from flowers and leaves of Eucalyptus camaldulensis and Eucalyptus tereticornis, specially in Australia, through the works of ELLIS & PFEIFFER (1990) 16 and PFEIFFER & ELLIS (1992) 41 permitted very interesting epidemiological investigations on C. neoformans, a capsulaled yeast by which SANFELICE 50, 51, in Italy (1894; 1895) attracted attention of medical class. BUSSE 8, in 1894, described the first human case of cryptococcosis under the presentation of a bone lesion simulating sarcoma. In this paper, the Brazilian researchers focused on this subject were pointed out, followed by the Author's experience with the C.G.B medium (L - canavanine, glycin and bromothymol blue) proposed by KWON-CHUNG et al. (1982) 24 with very good results. It was possible with such medium the study of 50 C.N.S. liquor samples, being 39 from AIDS patients (78%) and 11 from non-AIDS ones (22%). Thirty-seven out of the 39 HIV- positive patients (74%) were identified as C. neoformans var. neoformans and 2 (4%) as C. neoformans var. gattii. From the negative HIV, 8 (16%) were classified as C. neoformans var. neoformans and 3 (6%) as C. neoformans var. gattii. We could not perform the serotyping of the above referred samples. It is evident anyway that in Brazil there exist both varieties gattii and neoformans, agents of neurocryptococcosis, including AIDS patients. The importance of neurocryptococcosis, mainly among AIDS patients, is stressed here, showing once more the value of C.G.B. medium in the typing of C. neoformans in its two varieties. Also, it is of relevant importance the demonstration that some species of eucalyptus may act as "host-trees" of C. neoformans var. gattii.