Urbanization studies in the Pacific are greatly limited by data availability. The main indicators available are: rate of urban growth, proportion of urban population and size of the largest city. The cause of such situation is not so much a lack of data - censuses are regularly conducted by most countries - as an analysis gap. This dearth of data analysis is quasi general in PICs where most urbanization studies lack evidence support as regards geographic as well as demographic and social aspects of urban growth. This is the more surprising as some countries experience rapid urban growth and have already large urban populations and the impact on ability to manage urban growth is affected. This paper will address the process of urban growth in a theoretical approach with support of custom tabulation from the Kiribati 2005 census. It will briefly consider the process of urban growth from the viewpoints of its demographic components and geographical extension, and try to assess factors and causes of rural-urban migration, or answer the question: is there a rational to rural-urban migration? It will also estimate the consequences of the urban drift on socio-economic characteristics of urban population as regards qualification, labour force participation and family transformation. Special focus will be on rural-urban migrants. Finally, policy implications of urbanization will be briefly reviewed. It is desirable that similar studies are carried out using data from other PICs and mostly for those with large urban population and several cities like Fiji and PNG. However, the socio-economic characteristics of urban population and rural-urban migrants described here most probably apply to larger countries.