An apparatus for determining shear bond strength of a cement to be set within a wellbore penetrating a subterranean formation consists of a housing, a vertical rod which extends from the uppermost portion of the housing through the lowermost portion of the housing, a base plate for positioning onto the bottom of the housing and for supporting the lowermost portion of the vertical rod, and a test plate for positioning onto the top of the housing through which the uppermost portion of the vertical rod extends. The apparatus may further contain a push rod. Shear bond strength is determined by introducing into the housing a sample core of the formation prior to introduction of a slurry containing the cement. The force required to break the bond between the vertical rod and the set cement may be used to determine the shear strength between the casing within the wellbore and the set cement when the cement is hardened within the wellbore. The force required to break the bond between the set cement and the sample core may be used to determine the shear strength between the set cement and formation core when the cement is hardened within the wellbore.