Soil has an important role in the greenhouse effect as a net source or net sink of greenhouse gases. This study compared CO2 emission from broiler poultry manure (PMB) and hen poultry manure (PMH) in two different soils. A laboratory experiment was conducted to evaluate the decomposition of poultry manure by analysing carbon mineralisation. Jars were filled with soil, sealed, and placed in an incubator for 60 days, with periodic CO2 analysis. Higher emissions were found in soil amended with PMH; cumulative carbon released as CO2 was 800 mg C/kg in soil amended with PMH, and 600 mg C/kg with PMB. Data for cumulative CO2-C released from unamended and amended soils were fitted to four different kinetic models. With poultry manure, there were significant differences in the model parameters that represent the amount of total potentially mineralisable carbon and the mineralisation rate constant. After 60 days, the percentages of organic carbon mineralised for PMH were 40% and 26% for each soil, whereas the percentages were 20% and 12% for PMB.