In Australia, as elsewhere, finding and acquiring equity capital is one of the major problems facing start-up or growing entrepreneurial ventures. The informal venture capital market, comprising high net worth non-institutional private equity investors (or 'business angels') provides risk capital directly to new and growing businesses and has been shown to be considerably more significant than institutional providers as a source of finance for entrepreneurial businesses. Building upon research undertaken internationally, this study generated and evaluated data resulting from an investigation of 36 carefully screened Australian business angels. It focused upon three primary research questions: (i) Who are Australia's informal venture capitalists (business angels)? (ii) How do they behave? (iii) What are their investment criteria? The study initiates Australian angel research into the developing international continuum of informal venture capital research and can serve as the generator of empirically testable hypotheses for future research and theory development.