Abstract: The heat resistance of exponential phase cells of environmental barley isolates Enterococcus faecium BAR 1 and a hospital isolate Enterococcus faecalis MI 2 grown at 37 or 45 was determined at 55, 60 and 62.5 ° C for 30 min. From the survival curves, the decimal reduction times (D-values) were determined. Cells grown at 45° C showed higher D-values. It was determined that the exponential phase cells grown at 45 were more resistant to heat than the heat resistance of cells grown at 37° C. The cells of both isolates were found resistant to heat treatment at 55, 60 and 62.5 as compared with the control in which cells were grown at 37° C and treated at 62.5° C.