Proactive inhibition (PI) in motor short-term memory (STM) was investigated to determine if the PI effects commonly found in verbal STM are also present in motor STM. A simple linear positioning task was used in which a criterion position was presented to the blind-folded S (N = 72), with recall of the criterion after either 10 or 120 sec. The variable of greatest interest was the number (either 0, 2, or 4) of similar positions presented prior to the criterion, the previous positions and the criterion being recalled in reverse order following the retention interval. With 4 previous positions, Ss displayed greater absolute error and greater undershooting with algebraic error than with either 0 or 2 previous positions, indicating that PI effects were present in motor STM and that verbal and motor STM may be governed by the same set of laws.