The static postural control was analyzed in experienced dancers to determine the influence of long term balance training on everyday upright stance. To this end, we compared the postural stability between trained ballet dancers and sedentary subjects. Subjects stood 30 s with feet in four base-of-support configurations: in two configurations feet were in a parallel stance with malleolus 10 cm and 20 cm apart; in the others configurations feet were extrarotated with 20° opening angle and malleolus 15 cm apart, and 140° opening angle with malleolus close. Standing stability was assessed by measuring Center of Pressure (COP) trajectory on a force platform. For each trial we computed the following parameters: area and length of COP; root mean square and approximate entropy of anteroposterior (AP) and mediolateral (ML) oscillation of COP; area and frequency dispersion of the power spectrum density for AP and ML directions. The postural perturbation changed throughout the configurations but only the last condition was uncommon for the sedentary subjects. The two groups showed no significant differences for all parameters in the trials with more common feet configurations. In contrast, dancers exhibited statistically significant changes with respect to novices in the trials with complete feet extrarotation (140° opening angle). Thus, the learning gained by dancers during long term practice affects only the most challenging posture and not the common everyday upright stance.