Bongaart has performed research in a diverse set of topics, such as population growth and aging, mortality, population-environment links and demography related to the epidemiology of HIV/AIDS.
Bongaarts subsequently moved to the United States where he studied physiology and biomedical engineering at the University of Illinois and obtained his PhD in 1972, with a dissertation titled: "A Cybernetic Model of the Demographic Transition".
[1] In 1994 Bongaarts published the article "Population Policy Options in the Developing World" in Science.
[2] In an article in Nature in February 2016, Bongaarts showed projections of world population growth by 2100 and argued for worldwide spread of quality contraception and family planning within ten years to slow down population growth.
[11] In his nomination letter for the laureate Samuel H. Preston wrote: "I can think of no one who has contributed more to the battery of methods used to study population processes.