Hyperplasia or hypoplasia of muscles gradually leads to strabismus. Myogenesis-related genes are involved in extraocular muscle development, including myogenic differentiation 1 (MYOD1), myogenin (MYOG), retinoblastoma 1 (RB1), cyclin-dependent kinase inhibitor 1A (P21), cyclin‑dependent kinase inhibitor 1C (P57), insulin-like growth factor 1 (IGF1) and muscle creatine kinase (MCK). This study evaluated the expression of the above seven myogenesis-related genes by real-time quantitative RT-PCR in 18 resected extrocular muscles of patients with concomitant strabismus and 12 normal control muscle samples from one presumably healthy male 6 h after sudden mortality. We found that although there was a great divergence among the expression levels of 6 myogenesis-related regulatory factors, the relative expression patterns were similar in all the normal muscles, including the synergistic, antagonistic and yoke muscles. However, their expression levels in the 18 diseased extraocular muscles were abnormal; the expression levels of all the genes, with the exception of P57, were reduced in most of the diseased muscle tissues. These results imply that the abnormal expression of these myogenesis-related genes may contribute to concomitant strabismus.