A review of reported brucellosis cases among the Arabian American Oil Company’s [ARAMCO] Saudi Arab population was completed for the period from 1956 through mid-1985. Three distinct groupings of reported cases emerged: [1] the period from 1956 through 1982 had a mean of 1 1/5 cases reported per year [range 0-5] ; [2] the 1983 and 1984 reporting years had 23 and 25 cases; and [3] through mid-1985, 35 cases were reported. This represents an estimated rise in the crude rate of 0. 23, 1. 7 and 3. 3 cases per 10, 000 per year, respectively, for 1956-82, 1983-84 and 1985. A detailed examination of cases reported since 1983 was performed. Gorgraphic distribution was examined indicating a cluster of cases from the area served by ARAMCO’s Health Clinical in Abqaiq. A seasonal pattern is apparent with peak months being March, April and May. A positive history of unpasteurized milk/milk products consumption or exposure to animals [goats, sheep, camels] was indicated by 82% of reported cases during the 1983 to mid-1985 period. This review implicates endemic brucellosis in the local animal population as the most probable source of Brucella infection. This represents a significant public health problem, as local animals are a reservoir of infection for potential introduction of brucellosis into commercial dairy herds and are a continuing source of sporadic human brucellosis infections