To study the mutual interfering effects between cucumber and celery itercropping, along with the effect of planting density and pattern on yield of cucumber and as well, on celery, an experiment was carried out during 2006 in the horticultural fields of Tehran University. The experiment was performed, employing a complete randomized block design of fifteen treatments, each in three replications. Cucumber was planted as the main crop with three planting spaces (20, 30 and 40 cm), while celery being transplanted as the partner within the rows, between the rows and in a combination. The value of Land Equivalent Ratio (LER) was calculated. For all the treatments, a greater than 1 LER obtained, indicated the intercropping system as beneficial. The treatment of intercropping between cucumber and celery (planting space: 30 cm between the rows) produced the maximum yield. In single crop system, the treatments with planting spaces of 20 cm for cucumber and 30 for celery produced the maximum yields. According to the results obtained, an intercropping culture of cucumber and celery can be beneficially employed by the vegetable growers.