Urinary Tract Infection (UTI): This is the most common cause of urinary frequency, especially in women. Bacterial infection of the bladder or urethra leads to irritation of the bladder wall, resulting in frequent urination.

Benign Prostatic Hyperplasia (BPH): Enlargement of the prostate gland can compress the urethra, leading to urinary frequency, urgency, and nocturia in men.
Overactive Bladder: A condition characterized by a sudden, intense urge to urinate, often accompanied by urinary frequency and nocturia.
Diabetes Mellitus: High blood sugar levels can cause polyuria (excessive urine production), leading to urinary frequency.
Diuretic Use: Medications that increase urine production, such as diuretics, can cause urinary frequency as a side effect.

Kidney Stones: Although less common, kidney stones can cause severe pain and urinary frequency, and if left untreated, can lead to serious complications like kidney damage.
Bladder Cancer: Hematuria (blood in the urine) and urinary frequency can be symptoms of bladder cancer, making it a critical diagnosis not to miss.
Interstitial Cystitis: A chronic condition causing bladder pressure, pain, and urinary frequency, which can be debilitating if left untreated.

Tuberculosis of the Urinary Tract: A rare infection that can cause urinary frequency, hematuria, and other systemic symptoms.
Neurogenic Bladder: A condition resulting from nerve damage, affecting bladder function and leading to urinary frequency, incontinence, or retention.
Cystitis due to Radiation: Radiation therapy to the pelvic area can cause cystitis, leading to urinary frequency and other urinary symptoms.