Abstract: There is overwhelming evidence in sub-Saharan Africa that rural-urban migrants do not break links with their rural origins. The migrants are "men of two worlds" (Houghton, 1960) co-existing in two geographi­ cally separated households - one rural, the other urban. African rural-urban migration has persisted since the colonial period primarily because of the “urban bias" of the development process (Lipton, 1977) which confers many advantages to urban areas. The process has created "morselized households" (Kuznets, 1976) which tend to develop support systems at the polarised locales of migration, but which constitutes one family so divided by the process. Rural-urban migration is a direct outcome of economic disequilibrium which characterizes dual economies consisting of the modern sector which provides wage employment and the traditio­ nal subsistence sector in which the majority of population lives. Kenyan rural-urban migration exemplifies the sub- Saharan African case evolving from the country's colonial history. The modern sector of Kenya's economy evolved in the former "While Highlands" where a modern agricultural economy and a few small towns constituted the centre which was constantly dependent upon a large reservoir of cheap labour from the underdeveloped peri­ phery, made up of the so-called African Reserves. An urban primacy emerged in Kenya as the capital city of Nairobi amassed everything that represents development, with Mombasa at the Kenyan Coast becoming the gateway to international trade. Given the inadequacy of census data to provide dependable information about rural-urban migration, analysis of the process in Kenya has generally depended upon survey data which have been generated by a small number of migration or migration- centred studies. This paper attempts to demonstrate that Kenya's "urban bias" of development has resulted in temporary rural-urban migration which necessitates migrants "rural bias" in terms of their orientation, subsequent moves and their ultimate return to the permanent domicile. It consists of three sections : the first describes the configuration of development and the resulted migration in Kenya, placing their relationship in the context of Zelinsky's (1971) theoretical framework ; section two presents evidence of migrants'rural bias ; and the third section concludes the study.