Objective To investigate the expression of lin-28 homolog B (LIN28B) in adult head and neck rhabdomyosarcoma and its clinical significance. Methods Tumor tissues from 22 patients with head and neck rhabdomyosarcoma (aged ≥ 16 years) treated in our hospital from January 2009 to December 2015 were collected. The normal striated muscle tissues of 5 patients who underwent surgical treatment for other solid tumors were used as negative controls. The expression of LIN28B protein in tumor tissues was detected by immunohistochemistry. The relationship between the expression of LIN28B and clinicopathological parameters of adult head and neck rhabdomyosarcoma was analyzed, including sex, age, histological type, tumor size, lymph node metastasis, TNM stage, risk group, and cranial base bony erosion. Meanwhile, the relationship between the expression of LIN28B and prognosis was evaluated. Results Immunohistochemistry showed that LIN28B protein was negative in normal striated muscle tissues, while LIN28B protein was positive in adult head and neck rhabdomyosarcoma. Brownish yellow in cytoplasm was considered as positive staining. According to the histological score, the expression of LIN28B was low in 12 adult head and neck rhabdomyosarcoma patients (0-3 points) and high in 10 patients (≥ 4 points). LIN28B presented high expression in patients with non-embryonal rhabdomyosarcoma and with tumor size>5 cm (P=0.020, 0.030). The expression of LIN28B was not correlated with sex, age, lymph node metastasis, TNM stage, risk group or cranial base bony erosion (all P>0.05). The median follow-up period of 22 adult head and neck rhabdomyosarcoma patients was 78.4 months. The median progression-free survival (PFS) and median overall survival (OS) of the whole cohort were 12.4 months and 17.9 months, respectively. The 5-year PFS rate and 5-year OS rate were 11.4% and 13.6%, respectively. The patients with low expression of LIN28B had longer median PFS than patients with high expression (17.9 months vs 8.2 months, P=0.003), so was the median OS (23.5 months vs 10.9 months, P=0.009). Conclusion The expression of LIN28B is related to tumor size and histological type in adult head and neck rhabdomyosarcoma. LIN28B may play a potential role in the occurrence and progress of this tumor, and its high expression indicates a poor prognosis.