Sulfotransferase Family 1A Member 2 (SULT1A2) is a protein coding gene. Several studies have reported that SULT1A2 may have a chemical carcinogenic effect if expressed as a functional protein. The present study aimed to investigate the expression and potential role of SULT1A2 in bladder cancer (BC). Data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus databases were used to analyze SULT1A2 expression in BC. In addition, reverse transcription-quantitative PCR and western blot analyses were performed to detect SULT1A2 expression in BC cells and tissues. Immunohistochemistry analysis was performed on 100 formalin-fixed, paraffin-embedded BC tissues and corresponding adjacent normal bladder tissues (ANBTs) to verify SULT1A2 expression and determine the clinical significance of SULT1A2 in BC. Gene set enrichment analysis (GSEA) was performed to determine the potential biological processes and internal molecular mechanisms. The results demonstrated that SULT1A2 was highly expressed in BC tissues compared with ANBTs. Furthermore, high SULT1A2 expression was significantly associated with the staging of BC. Analyses of TCGA datasets and BC tissue microarray indicated that high SULT1A2 expression was significantly associated with a favorable overall survival in patients with BC. In addition, GSEA revealed pathways, diseases and biological processes associated with SULT1A2. Taken together, the results of the present study suggest that SULT1A2 acts as an oncogene in BC, and thus may serve as a biomarker for tumor staging and prognosis in patients with BC.