This paper reviews 46 cases of primary lymphoreticular tumours presenting in the orbit treated at the Christie Hospital between 1932 and 1969. Primary control of the orbital disease was readily achieved with a single exposure of 800 rad of orthovoltage X-rays to a single anterior field of 7 cm diameter and no case recurred in the orbit. The extent of the disease is a more important factor than the exact histological diagnosis in determining the prognosis, but none of five cases of benign lymphoma has developed disease elsewhere in a period of 5-7 years after treatment. The prognosis is good with a crude five-year survival of 54 percent, but if the disease is initially confined to the orbit 70 percent survive five years.