Purpose: Spasticity negatively affects the muscles and joints of the extremities and can be harmful to growing children. Children born with cerebral palsy do not have extremity deformities at birth but develop them over time. The goal is to reduce spasticity to avoid deformities. In this pilot study, we tested a non-pharmaceutical non-invasive method using an electrodress for six months. Material and methods: We included 16 children with cerebral palsy and Gross Motor Function Classification System (GMFCS I-V) age 2–16 y, median age 6.3 y. The intervention lasted 60 min every other day with reciprocal inhibition of the spastic muscle. Results: Passive range of motion (pROM) improved during treatment with a significant number of improved muscles after one (p = 0.000), three (p = 0.001) and six (p = 0.014) months. The spasticity level measured using the modified Ashworth scale (MAS) significantly decreased at one (p = 0.007) and six months (p = 0.011) and was almost significant after three months (p = 0.076). The modified Tardieu significantly decreased after one month (p = 0.030), but not after three (p = 0.392) or six months (p = 0.426). Conclusion: The electrodress has effects on spasticity levels and pROM. Further studies are needed to optimise the frequency and intensity of the current with respect to the effects on the level of spasticity.