Objective To study relation between expression of cyclin-dependent kinase like 5 (CDKL5) in gastric cancer tissue and clinicopathologic characteristics of patients with gastric cancer. Methods The expressions of CDKL5 mRNA and protein in 45 gastric cancer tissues and their corresponding adjacent tissues were detected by real-time quantitative PCR and Western blot methods respectively. Meanwhile the expressions of CDKL5 protein in gastric cancer cell lines including AGS and MKN-45 were detected by immunofluorescence method. Results The CDKL5 mRNA and protein highly expressed in the 45 primary gastric cancer tissues as compared with the their corresponding adjacent tissues (P<0.05). The results of univariate analysis identified that the age (P=0.033), vascular invasion (P=0.007), T stage (P=0.049), and TNM stage (P=0.041) were associated with the expression of CDKL5 mRNA in the primary gastric cancer tissues. The results of multivariate regression analysis showed that the vascular invasion (P=0.013) and TNM stage (P=0.024) were the important factors affecting the expression of CDKL5 in the primary gastric cancer tissues. The CDKL5 protein expressions were found at fragments with relative molecular masses of 107×103 and 85×103 in the primary gastric cancer tissues and gastric cancer cell lines. Conclusions CDKL5 mRNA and protein highly express in primary gastric cancer tissue and relate to vascular invasion and TNM stage. The CDKL5 protein expresses at fragments with relative molecular masses of 107×103 and 85×103 in primary gastric cancer tissues and gastric cancer cell lines suggest that CDKL5 has different expressing way in protein level.