Circadian genes were proven to play significant roles in tumor development and progression via coordinating various cellular processes. Though circadian rhythm disturbances both on the level of expression and genetic variant analysis have been associated with increased risk for many cancer types, none has investigated the potential effect of PER3 VNTR in bladder tumorigenesis yet. In this study, we aimed to assess PER3 VNTR's effect in terms of creating susceptibility to bladder carcinoma formation. Our second target was to enlighten the possible associations between PER3 genotypes and clinicopathological correlations in bladder carcinoma cohort and thus evaluate outcomes in bladder carcinoma prognosis. In this case-control study, 116 patients and 120 healthy controls were recruited. DNA was isolated from peripheral blood using the standard salting-out procedure and PER3 VNTR variants (ins/del polymorphism) were determined with PCR technique to distinguish the 5-repeats allele (401 bp) from the 4-repeats allele (347 bp). Though this exploratory analysis did not provide evidence supporting the role of PER3 VNTR in the onset of bladder carcinoma, it enabled us to make a risk assessment for the prognosis of bladder carcinoma patients. The survival times of patients decreased in the patient group (progression and cystectomy positive) for PER3 4/4 genotype and (recurrence, progression and cystectomy positive) for PER3 4/5 genotype. Results presented in this study are highly recommended to be investigated and validated in larger samples in different populations and ethnicities to generalize potential clinical utility.