52 (6.46 per cent) out of 805 women who aborted spontaneously in Gujarat state, India, were found to have positive Brucella agglutin. Infection with brucella was further confirmed by various serological tests (Rapid plate test, standard agglutination test, Rose Bengal test, Coombs' test, complement fixation test, indirect bacterial haemagglutination test, gel diffusion test and determination of C-reactive protein). Culturing 650 blood clots, 300 placentae and 800 samples of urine of women who aborted gave totally negative results. Women who were selected for this study immediately after admission to the Civil Hospital, Ahmedabad, India, came from rural areas and belonged to the farming community. They had a history of contact with animals and were of the lower socio-economic group. The relationship between brucellosis and spontaneous abortion is discussed. The aborted women would most probably have contracted the infection from their domesticated animals, since brucellosis is prevalent amongst the animals in the State of Gujerat.