Multiple sclerosis is a degenerative inflammatory disease that causes different musculoskeletal problems. Its impact has led to the study of treatment alternatives such as the use of invasive physiotherapy. In this study, we analyze the effects of ultrasound-guided percutaneous neuromodulation to a 51-year-old man suffering from multiple sclerosis and an associated hemiparesis in the left upper limb. A dry needling needle was placed in contact with the median nerve under ultrasound guidance and 10 trains of 10 seconds of electrostimulation with a frequency of 10 Hz and an impulse width of 240 µs were applied, with 10 seconds of pause between them. There was a significant improvement in the grip strength immediately after the treatment which increased progressively at 24 hours and at 4 days follow-up. There was also an improvement in the hand function, with a decrease in the time necessary to perform the 9 Hole Peg Test immediately after the treatment, which was maintained at 24 hours and at 4 days follow-up. Future studies with larger samples are needed to further test the effects of this invasive physiotherapy technique as well as its possible applications to other neurological conditions.