Primordial germ cells (PGCs), the progenitors of the gametes, migrate from the position where they are specified towards the region where the gonad develops. To reach their target, the PGCs obtain directional cues from cells positioned along their migration path. One such cue, the chemokine SDF-1, has recently been found to be critical for proper PGC migration in zebrafish and in mice. In Drosophila, too, a molecule that is structurally related to chemokine receptors and is important for PGC migration has been identified. The ability to visualize chemokine-guided migration at a high resolution in vivo in these model organisms provides a unique opportunity to study this process, which is relevant for many events in normal development and disease.