The toxic crystal protein (Mr 64,000) from a subspecies of the bacterium Bacillus thuringiensis has been solubilized and recrystallized yielding diffraction quality crystals. Crystals are obtained by a change in pH and ionic strength using Na2CO3. They can also be obtained by a change in ionic strength only using NaBr as the precipitant. The space group of both forms is C222(1) with a = 133, b = 116, c = 104 A and one molecule/asymmetric unit. Still photographs show reflections to 3.0-A resolution.