A preliminary investigation was carried out during 1985 to clarify the importance of some modern abattoirs in the epidemiology of brucellosis in Saudi Arabia. The standard plate agglutination test was used to screen serum sample collected from workers of 7 out of 9 slaughterhouses for the presence of Brucella agglutinins. Out of 745 serum samples [collected from 42 veterinarians, 52 veterinary assistants, 299 butchers, 258 laborers and 94 other occu-patients] 13 samples representing 1. 74% were positive reactors. The incidences among these workers were 7. 14% of the veterinarians. 2. 67% of the butchers and 0. 77% of the laborers. Since the serologically positive reactors did not show clinical symptoms of brucellosis, they were found to local hospital for further examinations and proper treatment. Further investigations are urgently needed to explore the possibility of Brucella infection among the huge number of workers at the popular abattoirs, popular kitchens, animal markets, and at animal aggregations, especially dairy farms, as well as the workers in the dairy and meat industries. The epidemiology of brucellosis among the abattoir workers was discussed. Coordination between ministries of agriculture, health, municipalities, defense and national guard, as well as university faculties of medicine and veterinary medicine, is essential to establish a national brucellosis control program