Why do factors of production, especially the labour, migrate from one region or sector to another? This question, which remains fundamental to economic and human resource development, has been a major topic among researchers. While considerable progress has been made in developing a theoretical model of migration, the empirical verification of this model using individual level data has remained unresolved. With the availability of Population, Labour Force, and Migration (PLM) Survey data, this paper attempts to develop a model of internal migration in Pakistan, to serve as a guiding paradigm to write down a model for meaningful estimation. Keeping in line with the literature, three types of variables have been identified as the possible determinants of migration. These variables relate to the possession of human capital, commitment to job and place of residence, and cost-related factors. After controlling for other variables, it was observed that, in general, migrants were selective especially in terms of age, education, and choice of occupation. These findings are consistent with the evidence from other developing countries.