A new technique for the recovery of Brucella cells from the blood of infected hosts employs filtration of laked blood specimens through membrane filters and permits the recovery of Brucella cells directly on solid media. The new method has proved to be at least as good as previously descr. blood culture methods and does not possess the disadvantage of cultivation in liquid media which is necessary in other methods. The membrane filter technique also appears to permit a quantitative estimation of the extent of bacteremia and should be applicable to blood cultures of other bacterial pathogens.