 [ Symptoms ] i have frequent urination at night what causes that [ Disease ] i do not know anything about you to blindly determine a specific cause not even your sex if you are male and over the age of 50 it could be bph benign prostatic hypertrophy if you are a female one would need to consider a urinary tract infection or variety of urinary tract problems and in either sex nocturia the medical name for this condition could be one of the signs of diabetes on a more simple case you could be drinking too much in the evening and not completely emptying your bladder see your medical provider this is really the only way to determine a reason and hopefully find a solution