The purpose of this study was to analyze the relationship between coaches’ professional playing experience and their professional coaching success. The sample (n = 134) included coaches who had the equivalent of three full seasons of head coaching experience in either Major League Baseball (MLB) (n = 46), the National Basketball Association (NBA) (n = 38) or the National Football League (NFL) (n = 50) as determined by the total number of games coached between the years 1997-2007. ANOVAs revealed no significant differences between coaches with more or less professional playing experience and professional coaching success as determined by professional winning percentage. Further, no significant relationship was found between professional playing experience and professional coaching success in MLB (r = -0.16), NBA (r = -0.05) or NFL (r = 0.00). It was concluded that professional playing experience was not a predictor of professional level coaching success. These findings support the notion that sources of knowledge other than playing experience may be necessary and useful in developing coaching expertise.