The objective of this study was to present an overview of the prevalence of spasticity after stroke as well as of test instruments and treatments. Recent studies show that spasticity occurs in 20%-30% of all stroke victims and in less than half of those with pareses. Although spasticity may occur in paretic patients after stroke, muscle weakness is more likely to be the reason for the pareses. Spasticity after stroke is more common in the upper than the lower limbs, and it seems to be more common among younger than older people. To determine the nature of passive stretch, electromyographic equipment is needed. However, the Modified Ashworth Scale, which measures the sum of the biomechanical and neural components in passive stretch, is the most common instrument used to grade spasticity after stroke. Treatment of spasticity with physiotherapy is recommended, although its beneficial effect is uncertain. The treatment of spasticity with botulinum toxin in combination with physiotherapy is suggested to improve functioning in patients with severe spasticity. A task-specific approach rather than a neurodevelopmental approach in assessing and treating a patient with spasticity after stroke seems to be preferred.