The plants are exposed to a wide variety of biotic and abiotic stresses; allelopathy is one of the important abiotic ones. Although allelopathy has been known as a problem in agriculture, nowadays evidences show that allelopathy has a beneficial role in weed management in different agroecosystems. Oat is one of the serious weeds of many fields; for instances, canola fields. In order to study the allelopathic effects of root and shoot of canola to control wild oat weed two separate experiments, germination and greenhouse, were done.Germination study was conducted as a completely randomized design with factorial arrangement and four replications under optimum conditions (16 h light and 25 0C) in germinator. The first factor was the kind of organ (shoot and root) and the other factor was concentration in five different levels (0, 20, 40, 60 and 80%) of stock solution of canola, and the oat examination union was petri dish including 20 seeds.Every day the petri dish situations were considered, after seven days some seed germination criteria including: germination percentage and rate, plumule and radicle length of seedlings were measured. Statistical analysis of data showed that all water extracts had negative effects on all of measured characteristics specially reduced radicle length of seedlings. In addition, seed germination reached to zero in 80% concentration of water extract of canola shoot. Moreover, in order to study allelopathic effects of canola on growth of wild oat another experiment including different combination of two different section (shoot and root) of canola and four different amounts (0, 5, 10, 15 gkg-1soil) of these sections was done. The design of this experiment was the same design of the germination study as a completely randomized design with factorial arrangement, but with three replications under greenhouse conditions. After six weeks the percentage and rate of emergence and shoot and root dry weight of wild oat weed were measured. The results revealed that with increasing the amount of different sections of canola, emergence rate and shoot dry weight significantly decreased, so that the minimum of emergence percentage and rate was in 15% shoot treatment. In general, although the negative effects of shoot were more than that of root on germination percentage and rate in both experiments, the inhibition of canola root on the other parameters in second experiment was more than that of canola shoot.