The growth and distribution of the population of Libya were studied along with the changes in the size and structure of the labor force and rhe country's economic development in order to assess the role that the population factor has played in economic development by analyzing the increase in the value of certain economic variables such as the per capita income and total consumption for the 1964-1971 period. The demographic data were primarily obtained from the 1964 census, preliminary results of the 1973 census, and from the special study conducted by the Ministry of Planning for evaluating the achievements of the first 5-year plan. Libya's population has been increasing rapidly in recent years. The inter-censal rate of population growth of 4.1% per annum between 1964 and 1973 was accepted for the purposes of this study. The Western Region contains about 64% of the population. Between 1964 and 1971 there was a continuous increase in the size of the working population. The working population was increasing at a slightly higher rate than that of the total population, so that the crude work participation rate recorded an increase of about 4% in about 8 years. Only about 1/2 of the economically active males with Libyan citizenship were employees, but as much as 80% of the economically active alien males were in that category, indicating that non-Libyans came to Libya to fill specific jobs. In 1964 2/5 of the working population were engaged in the agricultural sector and another 1/4 were at work in the services sector. The changes in productivity increased the Gross Domestic Product value during the study period irrespective of the price rise, but because of the rise in price levels, the increase was exaggerated.