This paper presents the design and fabrication of an incinerator meant to thermally treat (i.e. combust) domestic waste for the purpose of reducing its volume and destroying hazardous substances or pathogens present in the waste. A step grate package incinerator with a capacity of 100 kg/day was designed and constructed to combust domestic solid waste which otherwise cannot be economically recycled. The mass balance of the equipment was done to determine the amount of combustion air needed to completely burn the waste; likewise the heat balance was done to determine if an auxiliary burner would be needed. The performance test carried out on the waste – plastic, paper, rubber, leather, textile, wood and garbage – reveal a percentage decrease in volume between 78% – 95%.