Spasticity is a sequel of injuries of the SNC that interferes with the voluntary activity, causes delay or regression of the development, favors the appearance of deformities osteoarticulares and produces pain. The useful drugs in spasticity have studied little in children, the studies that there are comparisons against placebo, the tizanidina and the baclofen is used but they have not compared one. Objective: to determine the effectiveness in the reduction of the spasticity of the patients dealt with baclofen and tizanidina. Subjects: patients between 2 and 14 years with spasticity that attend to Hospital Infantil de la Misericordia. Materials and methods: nearly prospective longitudinal experimental test clinical, was realised initial clinical evaluation and four monthly controls of spasticity with the scales of Ashworth and modified Tardieu, degree of the dose of medicine according to the answer, evaluation of indirect effect and controls of hepatic and renal function. Results: 36 patients 17 in the group of Baclofen 19 deal with Tizanidina Improvement in 58% of the patients with Baclofen versus 56% of Tizanidina. The group of Baclofen improved in average 8 points in scale of Ashworth (p: 0.00) versus 5 in the group of Tizanidina (p: 0,01). Indirect effect: Baclofen 47% versus Tizanidina 63%. The tests of hepatic and renal function: 1 patient with elevation of transaminasas in the group of Baclofen. Retirements by indirect effect: Baclofen 2 Tizanidina 3 Conclusion: greater effectiveness and tolerance of the Baclofen versus Tizanidina.