While some of the macrofungi are highly substantial edible mushrooms which are rich in fibre, protein and vitamin, some of them are medicinal mushrooms which have beneficial components for health. An example of medicinal mushrooms is Ganoderma lucidum which became popular at biotechnological usage. In this study, the monokaryons of medicinal mushroom Ganoderma lucidum were used. Basidiospores were collected from the fruiting body of Ganoderma lucidum. Basidiospores were diluted with the sterile water. Then the spores were spread on CYM containing Petri dishes and incubated at 25 degrees C. Germinated single spores were selected by aid of microscope and monokaryon mycelia were produced. The growth rate of isolated eighty monokaryon mycelia were measured as cm at second, fourth and sixth day at 27 degrees C, 32 degrees C, 35 degrees C, 37 degrees C and 40 degrees C. The results were compared with our using temperature, 27 degrees C. The comparison of the growth rates of monokaryon mycelia that grew well at 32 degrees C with 27 degrees C showed that the difference of growth rates at the second and fourth day was significant (P<0.05), but at sixth day, the growth rates were similar both at 32 degrees C and 27 degrees C and the difference was insignificant. The mycelial growth rate was more slow at 35 degrees C than at 27 degrees C. The growth rates of monokaryon mycelia at 37 degrees C and 27 degrees C were significantly different (P<0.05) at the second and fourth day, but at sixth day the difference was found to be insignificant. Besides, the monokaryon mycelia of Ganoderma lucidum did not grow at 40 degrees C.