Botswana has completed the first part of the 'demographic transition', ie. a dramatic reduction of mortality, while fertility remained very high. The resulting extraordinary population growth creates enormous economic and social problems. This paper examines the spatial progression of the second and crucial part of the 'demographic transition', ie. a reduction of fertility, by comparing fertility between urban and rural areas and among rural districts, and between two generations of women in three contrasting villages. The analysis shows that the fertility transition' in Botswana is progressing in a geographically uneven manner: in some districts fertility is increasing due to the breakdown of traditions, while in others it is slowly declining due to modernisation or westernisation. The progression of the transition is not yet sufficient to contribute substantially to a reduction of overall population growth.