Abstract. Background. A cross-sectional survey on knowledge and perception of occupational biological risk among workers in several occupations was carried out in the industrial area of Rome. Methods. The study was carried out in the period of March-April 2010 using a questionnaire with 33 items on the following areas: a) socio-demographic data; b) perception of the biological risks in ordinary occupational activity; c) knowledge about biological risks; d) biological risks in the working environment. The questionnaire was submitted to a convenience sample of workers of an industrial area in Southern Rome. Results. 729 participants entered the study from the following work activities: food, catering, service, farming and breeding, healthcare, school and research (males 57.2%; mean age 37.4 years, SD = 10.9). Significant associations were found between different activity areas with respect to the relevance of the biological risk (p = 0.044) and the perception of the biological risk (p < 0.001). With respect to vehicles of infectious agents, the highest percentages of the most common biological risk exposures were: air and physical contact for the catering and food group, 66.7% and 61.90% respectively; air and blood for the health and research group, with 73.50% and 57.00% respectively; and physical contact and blood for the service group, 63.10 % and 48.30%. Significant difference of proportions were found about the prevalent effect caused by the biological agents was the occurrence of infectious diseases (59.90% food group, 91.60% health and research and 79.30% service group) (p < 0.001). The perception of knowledge resulted in a good rank (sufficient, many or complete) in the food and catering group, 78.3% with significant difference compared to other professions (p < 0.001). Conclusions. All participants show good knowledge the effects induced by biological agents and it is significant that almost half of the respondents are aware of the risks concerning allergies. Nevertheless, it is surprising that this risk is known mainly by workers of service, farming and breeding, to a greater extent than it is known by health workers.Key words: biological risk, knowledge, perception, workers.Riassunto (Conoscenza e percezione del rischio biologico occupazionale: risultati di una indagine condotta a Roma, Italia). Introduzione. È stato condotto uno studio trasversale nell'area industriale di Roma relativo alle conoscenze e alla percezione del rischio biologico occupazionale fra lavoratori di diverse tipologie. Metodi. Lo studio è stato condotto nel periodo marzo-aprile 2010 utilizzando un questionario che indagava sulle seguenti aree di interesse: a) dati socio-demografici; b) percezione del rischio biologico nelle attività lavorative ordinarie; c) conoscenza dei rischi biologici; d) rischi biologici nell'ambiente lavorativo. Risultati. Hanno preso parte allo studio 729 partecipanti delle seguenti categorie: alimentazione, catering, servizi, agricoltura e allevamento, sanità, scuola e ricerca (maschi 57,2%; età media 37,4...