SUMMARY— The effect of a monovalant ion like Na and divalent ions like Cu, Fe, Mn, Mg and Ca on the germination of spores of Bacillus stearothermophilus, B. cereus and B. megatherium both in the presence and absence of nisin was investigated. In the absence of nisin, Cu, Fe and Mn ions were more inhibitory than Ca and Na ions for the germination of all three kinds of spores. At 1M, Mg increased germination of different spores 3–9%. In the presencences nisin, both Ca and Mg increased the germination of B. stearothermophilus by 10.8 and 14.2%, of B. cereus by 30.4 and 19.9%, and B. megatherium by 6.6 and 30.9%, respectively. The rest of the ions increased inhibition of germination by nisin. The increase in germination by Ca and Mg was correlated with the release of DPA and is discussed.