This report presents the results of the 2019 Informal Sector Survey (ISS) conducted in Dar es Salaam Region from August to September 2019. The survey was conducted by the National Bureau of Statistics (NBS) in collaboration with the Ministry of Finance and Planning and Prime Minister’ Office-Labour, Youth, Employment and Person with Disability. The 2019 Informal Sector Survey is the third survey in series conducted in Tanzania Mainland since 1991 when the first post-independence survey was launched. The main Objective of the 2019 Informal Sector Survey (ISS) was to obtain comprehensive data on informal sector output resulted from productive agricultural and non-agricultural activities and corresponding intermediate inputs used in the production process. The results have been used to update the size of informal sector, its contribution to the Dar es Salaam Gross Domestic Product and identification of economic activities with high employment in Dar es Salaam Region which is crucial for social- economic policy design and review.