Objective: To investigate the Wnt5a expression in papillary thyroid carcinoma (PTC) tissues and its significance. Methods: The paraffin-embedded specimens that included tumor tissues and adjacent tissues from 47 postoperative pathology confirmed PTC patients, and 10 pairs of fresh surgical specimens of PTC and adjacent thyroid tissues were collected. Wnt5a expression in these PTC and adjacent tissue samples were detected by immunohistochemical staining and real-time PCR method, respectively. Results: In the paraffin-embedded specimens of 47 patients, Wnt5a positive expression rate was 68.09% (32/47) in PTC tissues and 6.38% (3/47) in adjacent thyroid tissues, respectively, and the difference between them had statistical significance (P<0.01); further statistical analyses indicated that Wnt5a expression was irrelevant to the age and sex of the patients (both P>0.05), but was related to their TNM stage and lymph node metastasis (P<0.05 or P<0.01). Examination of the 10 pairs of fresh surgical specimens showed that Wnt5a mRNA expressions in PTC tissues were significantly higher than those in their paired adjacent thyroid tissues (6.43±1.38 vs. 1.12±0.59, P<0.01). Conclusion: Wnt5a expression is increased in PTC tissue, which suggests that Wnt5a may be potentially involved in the occurrence and development of PTC.