Abstract: An apparatus for performing scrotal circumference measurement on bulls consisting of a casing having an interior cavity, an exterior surface with a concave portion and an opening in the casing providing access to the interior cavity. A gradulated flexible tape is coiled within the interior cavity of the casing. The gradulated flexible tape extends through the opening and has an end secured to the exterior surface of the casing adjacent the concave portiion such that the tape and the concave portion define a circular opening to accommodate a scrotal circumference. The graduations on the tape assign a value to the concave portion thereby providing an accurate circumferential measurement. A spring is positioned within the interior cavity of the casing providing a biasing force of between 1.26 and 2.26 kilograms of tension to draw the tape into the interior cavity of the casing.