The authors describe the experience of the smallpox laboratory diagnosis, during the first year of activity of a Unit prepared as a support to the Smallpor Eradication Campaign in Brazil. Frorn the specimens - 71 crusts and 16 vesicular pustular fluid - respectively 28 and 9 smallpox strains zoere isolated, and the agar-gel precipitation test was positive in respectively 21% and 25% of the specimens (table 1). Different periods of time were taken to the specimens reach the laboratory, what influenced the percentage of virus isolation (tables 2 and 3). The agar-gel test with the original specimens showed positive results only when enough material was available; the test, however, was used as a confirmation of virus isolation, using egg membrane with virus lesions. The results obtained by the laboratory in the last months will be presented and discussed in the next paper.