Corporate social responsibility (CSR) is a dramatically expanding area of activity for managers and academics. Consumer demand for responsibly produced and fair trade goods is swelling, resulting in increased demands for CSR activity and information. Assets under professional management and invested with a social responsibility focus have also grown dramatically over the last 10 years. Investors choosing social responsibility investment strategies require access to information not provided through traditional financial statements and analyses. At the same time, a group of mainstream institutional investors has encouraged a movement to incorporate environmental, social, and governance information into equity analysis, and multi-stakeholder groups have supported enhanced business reporting on these issues. The majority of research in this area has been performed on European and Australian firms. We expand on this literature by exploring the CSR disclosure practices of a size- and industry-stratified sample of 50 publicly traded U.S. firms, performing a content analysis on the complete identifiable public information portfolio provided by these firms during 2004. CSR activity was disclosed by most firms in the sample, and was included in nearly half of public disclosures made during that year by the sample firms. Areas of particular emphasis are community matters, health and safety, diversity and human resources (HR) matters, and environmental programs. The primary venues of disclosure are mass media releases such as corporate websites and press releases, followed closely by disclosures contained in mandatory filings. Consistent with prior research, we identify industry effects in terms of content, emphasis, and reporting format choices. Unlike prior research, we can offer only mixed evidence on the existence of a size effect. The disclosure frequency and emphasis is significantly different for the largest one-fifth of the firms, but no identifiable trends are present within the rest of the sample. There are, however, identifiable size effects with respect to reporting format choice. Use of websites is positively related to firm size, while the use of mandatory filings is negatively related to firm size. Finally, and also consistent with prior literature, we document a generally self-laudatory tone in the content of CSR disclosures for the sample firms.