Scholars have long been interested in the role of population and its impact on the economy of various countries, hence the theories on the subject. While Malthus’ population theory presents a very pessimistic view and is formulated in a context which does not correspond to the conditions of the modern world, it occupies the minds of a majority of economists. It is interesting to know, while Malthus himself either revised or weakened his views, the majority of economists still emphasize his earlier thoughts. For this reason, this study offers a concise review of his theory and point out the revisions which he had made earlier. The study also pays attention to the views of two other famous economists: John M. Keynes and Gary Becker. They also had a pessimistic view regarding the impact of population growth. Like the earlier writers on this subject they reformulated their earlier thoughts. The study considers the documents and the new ideas which contrary to the dominant pessimistic view emphasize the positive aspects of population growth. It is concluded that most of the economic problems considered as population problem are actually related to other factors such as weakness in planning and management, the rules and regulations of the economic systems dominating a country, behavior of human beings, wasting natural resources, etc.