In eukaryotic cells, sister chromatid cohesion (SCC) keeps newly replicated chromosomes tightly associated until the onset of mitosis, ensuring high-fidelity chromosome segregation and repair of DNA damage. In bacteria, molecular evidence for physical SCC had been lacking, although fluorescence imaging had demonstrated a short period of colocalization for newly duplicated loci. Lesterlin et al. set up a recombination-based system that probed the ability of Escherichia coli sister chromatids to interact physically. They found that, following their replication, sister loci were consistently involved in a cohesion step that lasted 10–32 minutes. Importantly, factors that are known to reduce the colocalization of sister loci in fluorescence assays had no effect on cohesion, suggesting that the two phenomena are distinct. The authors propose that cohesion ensures the availability of the sister chromatid for repair of damage to newly synthesized DNA and may also help to control the timing of chromosome segregation.