Rural-Urban migration is the most crucial component of internal migration of any country. It plays an important role in poverty reduction and economic development. In Bangladesh rural-urban migration is the most important factor for rapid urbanization. In urban centres slum is a popular destination for poor rural-urban migrants. More than 15 million people lives in the slums of six divisional cities of Bangladesh. Megacity Dhaka, capital of Bangladesh, alone holds about 3.4 million people in 4966 slums. This book focuses on the three slums including two largest slums of Bangladesh. This study reveals that predominantly migrants come from northern and southern part of the country. Majority of these migrants came after 1990. In most cases migrants left villages at a very early age, between their ages of 15 to 30. This study evaluates the migration objectives, status and the fulfillment of their migration objectives based on a survey on 373 randomly selected migrants. Getting easy access to informal economy and job searching are the predominant objectives of the migrants. Financial crisis, lack of job, river bank erosion are some significant reason for rural-out migration.