Patients with Parkinson's disease (PD) frequently exhibit problems with gait initiation, maintaining rhythmicity of the gait, turning, and may suffer from motor blocks, i.e., freezing of gait (FOG). All these issues contribute to higher risk of stumbling and falling. In this study, we tested the influence of functional electrical stimulation (FES) on gait in 9 patients with PD with history of freezing episodes. Patients were walking along the given path comprising standing up from the chair, passing through narrow doorways and turning. Besides regular walking, protocol also comprised walking while carrying tray with glass of water (dual-tasking). Patients' peroneal nerve of the leg which was estimated to be from the weaker side was stimulated during the swing phase in moments when gait "normal" pattern was impaired. Stimulation was triggered automatically based on heel switch placed in the shoe. Gait sequences with and without FES were recorded successively, and these gait patterns were compared afterwards. Results showed that FES decreased duration of double support phase and variability of stride duration and stride length. While stimulated, two patients did not experience motor blocks in a few places along the path where they otherwise had problems with FOG.