AimsThis study aimed to examine the involvement of glucose‐regulated protein 94 (GRP94) in oestrogen receptor‐α36 (ER‐α36)‐mediated oestrogen signalling in gastric cancer development.Methods and resultsA total of 130 formalin‐fixed and paraffin‐embedded gastric tumour samples with corresponding normal gastric and tumour‐adjacent tissues were used. High levels of GRP94 expression (2+ or 3+) were observed in 109 of 130 gastric carcinomas (83.85%) by immunohistochemistry, and in 13 of 18 tumour specimens (72.22%) with Western blot analysis. GRP94 expression was correlated positively with gender, tumour stage, lymph node metastasis and ER‐α36 expression (P < 0.05). Oestrogen treatment up‐regulated both GRP94 and ER‐α36 expression in gastric cancer SGC7901 cells. In addition, steady state levels of GRP94 protein were decreased in established gastric cancer SGC7901 cells with knocked‐down levels of ER‐α36 expression and in xenograft tumours formed by these cells. Forced expression of recombinant ER‐α36 in SGC7901 cells, however, up‐regulated the levels of GRP94 expression.ConclusionsGlucose‐regulated protein 94 is a downstream effector of ER‐α36‐mediated oestrogen signalling, and may be involved in ER‐α36 function during gastric carcinogenesis.