This research is a survey of unregistered businesses conducted in Mauritius between June 2008 and February 2009, simultaneously with Mauritius 2009 Enterprise Survey. 132 informal businesses were interviewed. The objective of World Bank firm-level surveys is to obtain feedback from enterprises in client countries on the state of the private sector, assess the constraints to private sector growth and create statistically significant business environment indicators that are comparable across countries. Informal survey questionnaires are a shorter, tailored to unregistered businesses, version of Enterprise Survey questionnaires. The topics include general information about a business, infrastructure and services, sales and supplies, crime, sources and access to finance, business-government relationship, assets, AIDS and sickness (for African region), bribery, workforce composition, obstacles to get registration, reasons for not registering, and benefits that an establishment could get from registration. Business owners or managers are interviewed face-to-face.