Research in knowledge representation and decision-making using verbal protocols has shown that in tennis, baseball, and volleyball experts have more sophisticated response selection during competition. This study was designed to compare the knowledge representation and the use of tactical knowledge of expert volleyball players to that of novice volleyball players. Ten members of a large southeastern university's varsity volleyball team and ten physical education majors enrolled in a volleyball class at the same university participated in game play and between point interviews to elicit knowledge representation and decision-making. This retrospective report conducted immediately following performance is seen as an accurate way to trace an individual's thoughts during motor performance (Ericcson and Simon, 1993). As well, the setters participated in concurrent talk-alouds during game play. Interviews were transcribed verbatim and coded using McPherson's model of protocol analysis (1987, 1993a) and NUD*IST, a qualitative data analysis program. Quantitative analysis (Kruskal-Wallis tests) of verbal report measures indicated experts generated more total, varied, and sophisticated conditions and actions whereas novices generated more goals. The difference in knowledge representation and the use of tactical knowledge by experts and novices was greatest in the quality of the representation and the content accessed by experts and novices during game play rather than the quantity. At a micro level of analysis experts accessed more tactical content (to locate, identify, and read the opponent) and more of their opponent's tendencies than novices. Novices accessed few player tendencies and few conditions to locate, identify, or read the opponent. Novices were primarily concerned with their positioning on the court and the location of the ball. At a macro-level of analysis the experts built two larger memory structures an action plan profile and a current event profile (processing of previous game events or past information about an opponent). The identification of action plan and current event profiles (McPherson, 1999a) of participants helped to identify problem solving activities and the basis for decision making during skill execution and volleyball game play. Experts generated stronger and more advanced action plan profiles and current event profiles than the novices generated. Current results also represent initial theory building (McPherson, 1999a) as more research using verbal reports and protocols is warranted comparing volleyball opponents of different ages and level of play.