This research examines investment in human capital, financial risk, industry sector and corporate governance mechanisms as determinants of the voluntary disclosure of intellectual capital in a sample of 443 UK listed company annual reports for the year 2003/2004. This year precedes 2005 and the adoption of International Accounting Standards by European Union Member States thus providing the context for the study under reduced mandatory regulation. Voluntary disclosure is measured by an index based on intellectual capital attributes disclosed in the narratives and illustrations of the annual reports. The benefits of signalling intellectual capital are expected to outweigh proprietary costs due to these disclosures. These costs may be more prevalent in innovative and technological companies. Corporate governance mechanisms enhance voluntary disclosure and reduce information symmetry more specifically in those companies found to have higher levels of intangible assets in their resource base. The results suggest that companies associated with reduced financial risk and accompanied by growth are characterised with higher levels of voluntary disclosure of intellectual capital. Voluntary disclosure of intellectual capital is enhanced when large companies operating in high-tech and innovative industries are characterised by investments in human capital. The results suggest that companies that are able to maintain adequate governance systems through segregation of executive and non-executive duties and to a less extent through the presence of experienced non-executive directors exhibit higher levels of voluntary disclosure.