IOM Bangladesh Needs and Population Monitoring (NPM) is part of the IOM’s global Displacement Tracking Matrix (DTM) programming, first launched in Cox’s Bazar district, Bangladesh in Spring 2017. The NPM Site Assessment (SA) routinely collects information on numbers, locations, movements and multi-secotral needs of Rohingya refugees in all areas most recently affected by the sudden influx. The SA was launched in February 2017 and four rounds of data collection were completed before the mass influx of August 2017 (March, April, June, July). Round 5 included the new influx, and was completed in September. The NPM SA collects information about the overall Rohingya population, including refugees who arrived before 25 August 2017. It does not collect information on the entire Rohingya population in Bangladesh, but in Cox’s Bazar district only. The NPA SA covers all sites where Rohingya refugees have been identified irrespectively of the location type, including makeshifts settlements, spontaneous settlements, host communities, and formal refugee camps. Information is collected by a team of 70 enumerators through field level key informant (KI) interviews using a closed-ended KoBo questionnaire. Enumerators are locally recruited and thus able to conduct interviews in Bengali, Rohingya, and Chittagonian. The latter, Chitaggongian Bangla, is highly similar to the Rohingya language. The findings of the KI interviews are triangulated at the field level through direct observations, and spontaneous community group discussions. Not planned ahead, these group discussions are a product of the interest paid to KI interviews conducted in the field and are an important element in giving a voice to the local population and identifying their opinions concerning needs and vulnerabilities. On average, during a two week data colleciton period a single round of the NPM SA collects approximately 1600 to 1700 interviews with individual KIs. The NPM SA contains two separate but interlinked phases; a baseline study and the full multisectoral needs assessment.