The primary pathway of cyanamide dissipation during under both aerobic and anaerobic conditions is the degradation to [14CO2] (i.e. complete mineralisation). Apart from the final degradation product CO2 no other major degradation products (> 10 % of applied radioactivity) occurred, neither under aerobic conditions nor under anaerobic conditions. Cyanamide degradation in soil both under aerobic and anaerobic conditions can be best described by using first order degradation kinetics. The following DT50 and DT90 values were calculated for the aerobic and anaerobic degradation of cyanamide in soil under laboratory conditions: DT50 aerobic: 0.5 days - 3 days, DT90 aerobic: 1.9 days, DT50 anaerobic: 34.7 days, DT90 anaerobic: 105 days. DT50 values of 6 to 12 days were found in one sand soil with a very low organic carbon content and with the lowest test concentration 6-fold higher than the maximum recommended application rate. Therefore these values can be considered as unrealistic worst case values. Cyanamide degradation in soil is influenced by the organic carbon content of soils, indicating that biotic degradation plays an important role in soil. Under field conditions cyanamide was degraded with a mean DT50field value of 1 day and a worst-case DT50field value of 1.63 days. Two weeks after application no cyanamide residues could be detected anymore and thus, the DT90field is less than 2 weeks.