During mid-January 2000 the plume from a fire, which destroyed 9000 ha of mixed vegetation in the southern part of the Cape Peninsula, passed over the Cape Point Global Atmosphere Watch station (34° S, 18° E). The smoke plume was characterized by a CO/CO2 emission ratio (ER) of 0.0548+/-0.0018mol/mol, typical for biomass burning. Measurements of total gaseous mercury (TGM) made during this episode provided Hg/CO and Hg/CO2 emission ratios of (2.10+/-0.21)*10-7 and (1.19+/-0.30)*10-8mol/mol, respectively. Based on the presently accepted CO source estimate for biomass burning of 621*103ktyr-1 (range 400-700*103ktyr-1), the ER(Hg/CO) suggests that the global mercury emission from biomass burning amounts to approximately 0.93 kt annually (range 0.51-1.14 ktyr-1). Similarly, based on a CO2 emission from biomass burning of 3460*103ktCyr-1 (range 3000-6200 ktCyr-1), the ER(Hg/CO2) suggests that the global mercury emission from biomass burning amounts to approximately 0.59 kt annually (range 0.38-1.33 ktyr-1), in good agreement with the emission estimated from the ER(Hg/CO). If supported by measurements from fires in other regions, mercury emissions from biomass burning of the order of 1 ktyr-1 could represent one of the major, hitherto neglected, sources of atmospheric mercury.