The biodiversity and concentration of environmental fungi in the hospital surgical area was monitored for 36 months. A total of 120 measures were made, 70% of which had fungal growth, a single genus being identified in 62%. Nine different genus were isolated (Penicillium, Aspergillus, Acremonium, Dactylaria, Fusarium, Cladophialophora, Alternaria, Candida and Rodothorula) with a clear predominance of Cladophialophora. Aspects that still must be resolved are discussed. These are: periodicity of the sample obtention, definition of the area of risk, interpretation of the counts and species considered pathogenic. At present, in spite of the large gaps in knowledge, the maintenance of continuous registry system of the environmental biosafety levels is fundamental, since the cause cannot be identified in most of the times when elevated fungal count is detected.