There are several reasons why urine may smell like ammonia. The most common cause is eating foods high in nitrogen like proteins, meats, eggs, and asparagus. Consuming large amounts of these foods can lead to a strong ammonia smell in urine. Another cause is urinary tract infections from bacteria in the kidneys, urinary tract, or bladder, which are more common in women. Insufficient water intake can also concentrate urine chemicals and cause odors. Other potential issues include liver or kidney disease.