Botulinum toxin type A (BoNT-A) has been reported to be an effective treatment for limb spasticity after stroke. However, the reduction in the spasticity after BoNT-A injection alone does not ensure an improvement in the active motor function of the affected limb. The aim of this study was to clarify the clinical effects of a BoNT-A injection, followed by home-based functional training on not only the passive but also the active motor function of the affected spastic upper limb in poststroke hemiparetic patients. Eighty poststroke patients with spastic upper limb hemiparesis were studied. The severity of hemiparesis was categorized as Brunnstrom stage of 3 for hand-fingers in all patients. BoNT-A (maximum dose of 240 U) was injected into the target muscles of the affected upper limb after a clinical evaluation using the modified Ashworth scale, range of motion, Fugl-Meyer Assessment, and the Wolf Motor Function Test. Following the injection, occupational therapists provided home-based functional training for each patient on a one-to-one basis. The follow-up evaluation was performed 4 weeks after the injection. A significant improvement was found in the modified Ashworth scale and range of motion. The changes in the Fugl-Meyer Assessment and the Wolf Motor Function Test indicated a significant improvement in the active motor function of the affected upper limb. In conclusions, our proposed protocol of a BoNT-A injection, followed by home-based functional training seems to have the potential to improve the active motor function of the affected upper limb after stroke, although the efficacy should be confirmed in a randomized-controlled trial.