This paper presents material for consideration by regional planners responsible for the possible reactivation of agricultural land on the periphery of Québec towns and cities. Two lots of fallow land situated in the city of Laval were studied. We have simulated the re-activation of modem agricultural enterprises on these representative unused semi-urban lots. We first estimated the probable purchase price of the lots to be studied and then projected the investment necessary to put the land into maximum production in specific agricultural enterprises. By considering the possible revenues to be derived from agricultural enterprises best suited to these lots, we established their economic possibilities. As a result of the study of these two cases, we are able to state that present conditions do not permit the spontaneous- reactivation of fallow land in the semi-urban areas of Québec for agricultural purposes, principally because of the prohibitive cost of land purchase.