Organohalide respiring bacteria (OHRB) are major contributors to global halogen cycling and environmental attenuation of anthropogenic halogenated pollutants. OHRB are typically minor populations in microbial ecosystems and the strategies employed by these fastidious bacteria to persist and sustain functional stability remain unclear. The long-term viability of bioremediation technologies is impacted by washout of OHRB populations and the loss or divergence of functional genes in bioaugmentation cultures. Here, we evaluate the importance of microdiversity among Dehalococcoides, a prominent genus of obligate OHRB, in sustaining dehalogenation within mixed communities.