The ability of relaxation is a necessary component for a good function of the pelvic floor muscles (PF). The importance of a relaxation technique for the PF has not been paid much attention in children either in urological examinations or treatments. The aim was to seek postures with optimal relaxation of the PF for use in clinical practice with girls. The relaxation of the PF and adjacent hip and abdominal muscle groups was studied by using surface electromyography (EMG) and a polygraph writer in 20 healthy volunteer girls, 6 and 10 years of age. They were placed in three different postures with their legs supported and unsupported. In postures with supported legs, the relaxation was observed in 94% recorded from the PF and in 97% from the adjacent muscles. EMG amplitudes from the PF and adductor muscles were significantly higher in postures with unsupported legs compared to postures with supported legs (p less than 0.05). The present study indicates that the optimal relaxation of the PF can be achieved by adequate leg support. This can be important to apply particularly in clinical situations such as urodynamic investigations, in uro-biofeedback training and for the design of pelvic floor exercises for girls.