The aim of this study was to investigate KAI1/CD82 protein expression in human nasopharyngeal carcinoma (NPC) cell lines and human NPC tissues. Immunohistochemistry and western blot analysis were used to detect the localization and expression levels of the KAI1/CD82 protein in five human NPC cell lines. Immunohistochemistry was also conducted to detect the expression of the KAI1/CD82 protein in 70 NPC tissues and 30 non-neoplastic nasopharyngeal tissues. The levels of KAI1/CD82 protein expression were found to decrease as the metastatic potential of cells increased. The expression rate of KAI1/CD82 protein in the NPC tissues (44.3%) was significantly lower than that in the non-neoplastic nasopharyngeal tissues (70.0%) (P<0.05). KAI1/CD82 protein expression in the NPC tissues was not associated with clinical parameters, including gender, age, histological type and T stage, and the positive expression of KAI1/CD82 decreased with increased N staging. The level of KAI1/CD82 protein expression was increased in different human NPC cell lines. The KAI1/CD82 gene was highly expressed in cells with low metastatic potential, while low expression was observed in cells with a high metastatic potential. In addition, the KAI1/CD82 gene was expressed at low levels in nasopharyngeal carcinoma tissues, while high expression was identified in non‐neoplastic nasopharyngeal tissues, and was associated with lymph node metastasis. These results indicated that the KAI1/CD82 gene may be involved in the occurrence, development and metastasis of nasopharyngeal carcinoma.