Integrating for-profit providers with charitable providers raises many questions about tax exemption. The traditional criteria for determining tax-exempt status that apply to hospitals do not necessarily apply to integrated delivery systems because of their hybrid nature. The appropriate Internal Revenue Service (IRS) rulings and issues must be understood and adhered to before an integration can be structured in the most tax-efficient way. Reasonable as such a course of action seems, it is somewhat difficult because both the integrated delivery system concept and the IRS rulings that apply are evolving. In a time of flux, this article serves as a timely if temporary guide.