Results of various epidemiologic studies suggest that bacteriuria and urinary tract infection (UTI) occur more commonly in women with diabetes than in women without this disease. Similar findings have been demonstrated for asymptomatic bacteriuria (ASB), with ASB being a risk factor for pyelonephritis and subsequent decline in renal function. Although ASB is not associated with serious health outcomes in healthy patients, further research needs to be undertaken regarding the impact of ASB in patients with diabetes. Patients with diabetes often have increased complications of UTI, including such rare complications as emphysematous cystitis and pyelonephritis, fungal infections (particularly Candida species), and increased severity and unusual manifestations (e.g., gram-negative pathogens other than Escherichia coli). Anatomic and functional abnormalities of the urinary tract are also associated with diabetes. Such abnormalities result in greater instrumentation of the urinary tract, thereby increasing the risk of secondary UTI. In addition, these abnormalities complicate UTI and require specialized treatment strategies. There is a greater likelihood of UTI affected by antimicrobial resistance or atypical uropathogens, and the risk of upper tract involvement is increased. Pre- and posttherapy urine cultures are therefore indicated. The initial choice of empiric antimicrobial therapy should be based on Gram stain and urine culture. Choice of antibiotic therapy should integrate local sensitivity patterns of the infecting organism. Fluoroquinolones are a reasonable empiric choice for many patients with diabetes. For seriously ill patients, including patients infected with Pseudomonas spp., such agents as imipenem, ticarcillin-clavulanate, and piperacillin-tazobactam may also be considered. Treatment of ASB in patients with diabetes is often recommended to prevent the risk of symptomatic UTI. However, the management of ASB in patients with diabetes is complex, with no single preferred approach.