Clinical studies were carried out in the period of 2003-2008 at the Provincial Children’s Rehabilitation Hospital in Ameryka near Olsztyn (Poland). The study involved a group of children and youths exhibiting spinal deformity progression in idiopathic scoliosis (IS) of more than 5o per year according to the Cobb scale. Four hundred and fifty patients between 4 and 15 years of age were divided into three groups (n = 150). Group I received 2-hour and group II 9-hour treatment of Lateral Electrical Surface Stimulation (LESS), respectively, whereas group III (control) was treated only with corrective exercises for 30 minutes twice a day. LESS was performed as 24-month treatment with the use of a battery-operated SCOL-2 stimulator manufactured by Elmech, Warsaw, Poland. The effectiveness of this method was confirmed in the treatment of spinal IS in children and adolescent patients, especially when the initial spinal deformity does not exceed 20o according to the Cobb scale. A short-duration electrostimulation – 2 hours daily – wasfound to produce results similar to those obtained after overnight, 9-hour electrostimulation. Moreover, the analysis of the Harrington prognostic index F confirms the positive effect of LESS in both groups of patients (2 h and 9 h of LESS).