To study the gene persistence in the soil environment, soil samples were collected from sugarbeet (Beta vulgaris) and chicory (Cichorium intybus) experimental fields just before harvest. They were homogenized, mixed and stored at constant humidity in a non-heated room. Sub-samples of soils were subsequently collected at regular intervals, dried and sieved through a 1.8-mm mesh before DNA was extracted. Specific primers were then used for the detection of plant DNA by hot start polymerase chain reaction. Results reveal that, under laboratory conditions, transgenic and non-transgenic sugarbeet DNA was still detected after 25 days incubation in the soil taken from a sugarbeet experimental plot while detection of chicory DNA was still possible after 50 days incubation in soil taken from the chicory experimental plot. This might be in correlation with the stronger resistance of chicory radicles to decomposition as compared to radicles from sugarbeets.