Isolates of the yeasts Candida membranifaciens, Rhodotorula mucilaginosa and Pichia guilliermondii obtained from healthy apples were evaluated as potential bio. control agents for apple gray mold caused by Botrytis mali and B. cinerea. In-vitro volatile metabolites emitted from all yeast isolates inhibited the mycelial growth of B. mali and B. cinerea by 82.7 to 97.7 and 81.2 to 98.3 percent, respectively. Each of the yeasts significantly reduced the decay area in apples inoculated with the pathogens C. membranifaciens A2, A4, A5 and P. guilliermondii A6 had the greatest effect on decay reduction at 4oC, 20oC and 20±3oC. The populations of C. membranifaciens A2 and C. membranifaciens A5 during the experiment increased in apple wounds at 4oC.