AbstractWe investigated the effect of cigarette smoking on pathological staging in clinically low-risk patients. Data of 59 patients who were diagnosed with bladder tumor for the first time and had a single lesion radiologically and endoscopically smaller than 3 cm were investigated retrospectively. 33 patients who smoked were classified as Group I, and 26 patients who did not smoke were classified as Group II. Pathological diagnoses of the patients in both groups were compared. The mean age of the patients were 64.8 (20–86) years. In Group II, 5 (19.2%) were female and 21 (80.8%) were male (p < 0.05). Nine patients (27.3%) in Group I and 18 patients (69.2%) in Group II had Ta disease (p < 0.05). Nineteen patients (57.6%) in Group I and 5 patients (19.2%) in Group II had T₁ disease (p < 0.05). The number of patients with low grade (LG) tumor were 8 (24.2%) and 19 (73.1%) in Group I and in Group II, respectively (p < 0.05). The number of patients with high grade(HG) tumor were 25 (75.8%) and 7 (26.9%) in Group I and in Group II, respectively (p < 0.05). TaHG was detected in 9 (27.3%) patients in Group I. In contrast, no patients in Group II had TaHG disease (p < 0.05). The number of patients with T₁HG was 17(51.5%) patients in Group I and 2 (7.69%) patients in Group II (p < 0.05). Smoking is associated with pathologically HG and stage in patients with first time bladder tumor which is single and smaller than 3 cm.