Dissipation of the fungicides famoxadone and trifloxystrobin in basidiocarps of Agaricus bisporus was studied in mushroom growing rooms. The mushroom samples taken at all three consecutive production flushes following single or split applications of the fungicides were extracted with solvents and the residues were determined by using a gas chromatograph equipped with an electron capture detector (GC-ECD). Recoveries from the fortified control samples ranged from 87 to 105%. Following drench applications at 0.1-1 g/m2 of culture bed area, the highest famoxadone residue determined in basidiocarps was 0.1447 mg/kg. Analysis of trifloxystrobin revealed a quantitative relationship between the application rate (0.8-1.8 g/m2) and the residue levels of both the parent compound and its acid metabolite. The maximal combined residues of trifloxystrobin and its metabolite were 0.1313 mg/kg. Short- and long-term dietary risk assessment for both fungicides was carried out using consumption data from World Health Organization and the UK Pesticide Safety Directorate's Ten Consumer Model. The potential acute and chronic residue intakes via mushroom consumption were below toxicologically significant indicators.