Peat moss has been found to be an effective ‘organic matrix’ for the absorption and degradation of diazinon in experimental disposal pits. High concentrations of diazinon sorbed onto nutrient‐enriched commercial grade peat moss were rapidly degraded. Pits treated with diazinon concentrations ranging from 4000 to 32000 mg kg−1 contained less than 1 to 7 mg kg−1 after 18 weeks. Initially, degradation probably was due to hydrolysis resulting from the effects of heat, moisture, low pH and some microbial activity. Further degradation of the hydrolysis product, IMHP, was most likely due to microbial activity. The results obtained suggest that a managed degradation pit, containing a nutrient‐enriched organic matrix (peat moss), might provide a useful means for absorbing and neutralizing waste pesticide formulations because the materials used in this system are readily available and the system may be regenerative so that it can be used repeatedly.