Urothelial carcinoma of bladder (UCB) in African-Americans (AA) presents as more advanced disease at diagnosis and has lower 5-year survival rate, compared to Caucasians. The clinical diagnosis of higher grade and stage can be attributed to a more aggressive disease course in AA. Given the clear association between CA and aggressiveness, we hypothesized that AA have a higher incidence and severity of CA in bladder tumors as compared to Caucasians. To test this hypothesis, we developed an innovative method to quantitate the degree of CA (both numeric and structural) within tumor samples and defined a measurable index called the Centrosome Amplification Score (CAS). Our results demonstrate that bladder tumors from AA had significantly higher CA, particularly structural centrosome amplification (CASm) compared to grade-matched Caucasian patients suggesting racial disparity at the organellar level (p<0.05)