This French GEOCAP registry-based case-control study evaluated childhood acute leukemia risk in relation to residential proximity to high-voltage overhead power lines and modeled ELF magnetic-field exposure. It reports an increased risk for children under 5 living within 50 m of power lines, particularly when restricting to high-quality geocoded addresses. However, modeled ELF-MF exposure >0.3 µT was not associated with increased risk, and the authors suggest proximity may capture other factors and call for further research and precaution.