Records of all patients diagnosed as having malignant lymphoma in Israel between 1960 and 1964 were reviewed. The mean annual incidence for all cases was 8.3 per 100,000: 9.5 per 100,000 in males and 7.2 per 100,000 in females. The incidence rates and age distribution of lymphosarcoma and reticulum cell sarcoma were similar, with an abrupt rise around the age of 50 and steady increase in older age groups, in contrast with Hodgkin's disease where a bimodal age distribution was present. Lymphoma incidence was higher among patients of North African origin in younger age groups and among European patients in older age groups, but no differences were observed in incidence between the newly arrived and more veteran immigrants. A significant June peak was found in the first diagnosis of lymphosarcoma and reticulum cell sarcoma among adult males, but not among females, nor in childhood. This finding remains largely unexplained.