Bladder wall calcification is an under-reported adverse effect of intravesical mitomycin C therapy. We report our experience of a man who developed extensive bladder wall calcification within three weeks of being treated with just a single 40 mg dose of intravesical mitomycin C for non-muscle invasive, low-grade transitional cell carcinoma of the bladder. To date, only six other cases were reported in the scientific literature in English, all of which used higher doses of mitomycin and had a longer time to diagnosis than this case. We compared the salient points of this case with previously reported cases.