The paper presents an analysis of plant cover influence on the soil temperature. In the years 1971-1980 the soil temperature of bare fallow and of soil under lawn was recorded in the Agrometeorological station in Puławy. Soil temperature measurements were taken 3 times per day at the depths of 5, 10, 20, 50 cm, and once a day at the depth of 100 cm. Differences of temperature at the examination sites are presented in the form of graphs. Bare fallow temperature values are represented as a straight line, but the values of the difference in soil temperature between the lawn and the bare fallow form as curve below or above the straight line of the bare fallow. The soil temperature under the bare fallow was higher in the summer period than the soil temperature under the lawn, as opposed to the autumn-winter period. Mean minimum soil temperature was lower in the field with bare fallow, but mean maximum soil temperature was higher. Plant cover decreased the amplitude of the soil temperature and reduced the level of temperature extremes.