Urinary tract disorders have long been the spotlight of aerospace medicine due to its potential of leading to the disability of aviators under circumstances of great stress. Hematuria is a siren, implying a variety of causes such as urinary tract infection, calculi, prostatitis, prostate cancer and bladder cancer, which may result in grounding. Despite there are many reasons that can be grounded, urinary tract disorders are commonly self-recoverable or can be cured. Aviator can be temporarily grounded and return to his work after treatment or can be given waiver consideration. Urinary tract calculi and prostatitis are the two conditions that can cause sharp pain leading to the disability of aviators under G forces or vibration. Thus, flight surgeons should keep in mind the potential hazards of these potential incapacitating conditions. Aviators with these conditions should be educated and closely monitored to avoid mishaps.