This book begins with the introduction to the basic need of health care system, how the resources available for health care system are being limited. It describes the importance of need in oral health and how to assess those needs. This monograph also includes some important terminologies related to the topic, its concepts, models and studies done to estimate different types of need. The distribution and severity of oral diseases varies between and within areas. Unacceptable inequalities exist with more vulnerable, disadvantaged and socially excluded groups experiencing more oral health problems. An oral health needs assessment is a tool for identifying the oral health care needs of a population to target resources towards improving the oral health of those at specific risk or in undeserved population subgroups.