Previous research has proposed four competing views on an individual's fertility following a move from one social context to another. Each view has received support but has also been challenged in the literature. This study contributes to the existing discussion on fertility by providing an analysis of the effects of internal migration on the fertility of post-war Austrian and Polish female cohorts. The study is based on retrospective event-history data and applies intensity regression to both single and simultaneous equations. The analysis shows, firstly, that natives in urban areas in general and in large cities in particular have lower fertility compared with non-migrants in rural areas, both in Austria and Poland. Secondly, it reveals that people who move from one place to another adopt the fertility behaviour that dominates at the destination. Thirdly, we observe an elevated first-birth risk for women who move because of union formation, and a short-term postponement of childbearing for those who settle in a large city. The country comparison shows some differences in fertility variation across settlements, but overall the results are quite similar, despite the different post-war societal contexts of the two countries. Copyright © 2006 John Wiley & Sons, Ltd.