Wood is one of the most important natural resources, which has its use in almost every area of today’s modern world. Its importance is derived mainly from its many positive features. On the other hand, one of the biggest negative aspect of wood is its flammability. This diploma thesis focuses on the effect of fire proof treatment applied to Scots pine (Pinus sylvestris L.) and Sessile oak (Quercuspetraea (Mattusch.) Liebl.) samples. The assessment is based mainly on stating the fire characteristics, specifically the gross calorific value and oxygen index through standardized testing methods. A certain number of samples were treated with a fire retardant coating called FLAMGARD, the application of which was in two layers and impregnation lasting 24 hours. The average values of the gross calorific value at 0 % moisture were between 18 716 - 22 298 J.g-1. For the oxygen index, values of 23,8 - 65,5 % were measured at the current wood moisture. The most unfavorable results came from the untreated samples, which proves the used fire retardant’s effectivity. From the means of apllication, the 24 hour impregnation proved to be more effective.