Breeding-induced endometritis in horses seems to be down-regulated by certain components in the seminal plasma. These components are most likely some of the proteins in the seminal plasma in the stallion ejaculate, the so-called spermadhesins. This study aimed to recognize these proteins and determine their quantities in different fractions of the ejaculate. Fractionated ejaculates from four stallions were used to determine the presence and amount of proteins by way of size-excluding chromatography. All former known proteins, except two, were recognized in this study.