The predictive value of silver stained nucleolar organiser regions (AgNORs) was assessed in 229 patients with transitional cell bladder cancer followed up for over 10 years. The AgNORs were enumerated in pretreatment biopsy specimens. The AgNORs were related to clinical stage (T) (P = 0.0111), papillarity (P less than 0.0001), WHO grade (P less than 0.0001), DNA ploidy (P = 0.0010) and S-phase fraction (P less than 0.0001). Tumours presenting with pelvic lymph node involvement (P = 0.0085) or metastasis (P = 0.0780) at the time of diagnosis had more AgNORs than tumours confined to the bladder wall. Progression in T-, N- and M-categories (P = 0.0010-0.0030) was related to AgNORs and consequently they predicted bladder cancer related survival (P = 0.0005). The diploid tumours could be regrouped according to survival by AgNORs (P = 0.0001). In papillary tumours AgNORs predicted progression (P = 0.0110) and survival (P = 0.0038). In Ta-T1 tumours AgNORs predicted progression (P = 0.11) and survival (P = 0.0751) and also in T2-T3 tumours AgNORs contributed to survival significantly (P = 0.0039). The AgNORs subdivided WHO grade III tumours according to their ability to progress during the follow-up time (P = 0.0711). In a multivariate analysis AgNORs predicted progression independently in Ta-T1 category (P = 0.0165). AgNORs predicted recurrence free period like SPF (P = 0.0010). In conclusion, AgNORs are inferior to classic prognostic factors or DNA flow cytometric variables in muscle invasive bladder cancers whereas they have independent predictive value in superficial cancers.