We have demonstrated an all-optical memory by using InGaAsP/InP buried heterostructure photonic crystal (BH-PhC) lasers. We achieved distinct optical injection locking bistability in an ultra-compact active region (4 × 0.3 × 0.16 μm3) with only 25 μW pump power in the PhC waveguide, which is two orders less than previously reported optical memories based on other bistable semiconductor lasers. Dynamic memory operations were achieved with pump power of 100 μW and switching power of 22 μW and 71 μW in the PhC waveguide. Fast switching times of about 60 ps were achieved. To the authors' best knowledge, this is the first demonstration of PhC laser-based all-optical memory.