Multiple stagingofanaerobic digestion has been investigated as a means of optimizing the bioconversion of solid waste to methane fuel gas. Stage separation was achieved by pH control of the acid production stage. The results obtained from a laboratory‐scale experimental program are promising. The acidogenic stage was operable at 22°C without sacrifice of methane productivity. There was essentially no difference between the gross energy conversion efficiency of the single vs. multiple stage systems. The methane production stage off‐gases were enriched for methane with a partial pressure averaging 0.8. Multiple staging provided greater stability than did the single stage digesters.