Vesicular stomatitis virus contains single-stranded ribonucleic acid of molecular weight 3.6 X 106 and three major proteins with molecular weights of 75 x 103, 57 x 108, and 32.5 X 103. The proteins have been shown to be subunits of the surface projections, ribonucleoprotein, and matrix protein, respectively. From these values and from estimates of the proportions of the individual proteins, it has been calculated that the virus has approximately 500 surface projections, 1,100 protein units on the ribonucleoprotein strand, and 1,600 matrix protein units. Possible models of the virus are proposed in which the proteins are interrelated.