Given binary data transmission encoded using a Reed-Solomon (RS) code and employing binary sync-words (markers) for synchronization, we calculate the probability of finding the sync-word in the codewords of the RS code as P_S. We give analytical expressions for calculating P_S, which is applicable to RS codes. Knowledge of PS can be used to calculate the probability of finding a sync-word that is used as a marker in RS encoded data, P_T. The probability P_T is called the false acquisition probability in the synchonization of RS encoded data.