Bladder leiomyosarcoma is a unique mesenchymal tumour, accounting for less than 0.5% of all primary bladder malignancies. Bladder leiomyosarcoma used to be treated with radical surgery in either old or young patients, often resulting in significant impact on the patients's quality of life after surgery. We report on a case of bladder leiomyosarcoma in a 31-year-old female who was treated with partial cystectomy. Fortunately, no tumour metastasis or relapse was observed during the 7-year follow-up period and the patient now has a good quality of life. We found that partial cystectomy may be an acceptable option to treat bladder leiomyosarcoma in the low MSKCC (Memorial Sloan-Kettering Cancer Center) stage.