This paper aims at analysing, both theoretically and empirically, possible determinants of firm's demand of occupations. Even if traditionally neglected within economics literature, this issue can, in fact, be very useful for Economics, as this paper tries to shows. The theoretical analysis devotes a particular attention to find a preliminary link between the need for occupations and the theory of the firm. The empirical analysis is based on a dataset built using data from the 1996 "Analisi Excelsior", a survey on Italian firms occupational needs. This information have been merged with the balance sheet individual data of the same sample of firms. The dataset so built allow then to look for eventual relations between demand of occupations and some firms characteristics (like vertical integration, tangible and intangible assets equipment, productivity) Acknowledgments. This work continues a study on the demand of professions started with Bruno Contini and Giovanna Garrone. A preliminary analysis based on the same data (whose source is the "Analisi Excelsior") has been published in Contini, Garrone and Novarese (2000). A previous version of the present paper was presented at the Conference "Understanding Skills Obsolescence: Theoretical Innovations and Empirical Applications", ROA/SKOPE, Maastricht, May, 11-12, 2001.