Aim: To investigate the electrophysiological findings of sciatic nerve injury following intramuscular injection and follow-up progression. Materials and methods: Included in the study were 26 patients (16 men, 10 women) with sciatic nerve injuries due to intramuscular injections who were admitted to our electrophysiology laboratory. The age, sex, and body mass index (BMI), along with the clinical and electrophysiological findings of each of the patients, were recorded. Tibial and peroneal nerve motor conduction studies, sural and superficial peroneal nerve sensorial conduction studies, and needle electromyography were performed. The patients were reevaluated for electrophysiological evaluation at 3 and 6 months and 1 year after the procedure. Results: The mean age was 44.85 ± 22.71. All of the patients had peroneal involvement; 22 had tibial involvement, 6 had a total lesion at the peroneal and tibial nerve, 18 had severe or moderate involvement (70%), and only 8 (30%) had mild involvement. Recovery was poor, except for those with mild involvement. Conclusion: Sciatic nerve injury due to intramuscular injection is a signifi cant health problem. Although most of the lesions were moderate, recovery was inadequate. Electrophysiological examinations give significant clues about the prognosis and treatment.