The diagnosis of acute community-acquired bacterial urinary tract infections (UTIs) in adult men presently recognizes four key clinical entities: cystitis, prostatitis, pyelonephritis, and epididymo-orchitis, each with distinct diagnostic criteria. Bacteriuria of clinically undetermined significance, defined as documented bacteriuria with non-specific systemic symptoms (e.g., confusion, functional decline, or isolated fever) but no localized UTI signs, is common in elderly patients and requires evaluation with sepsis risk scores so as to avoid unnecessary antibiotics. Urinary colonization, frequent in older men, does not warrant treatment unless prior to urological procedures. Cystitis is diagnosed by local symptoms (dysuria, urgency, suprapubic pain), absence of fever, and positive urine culture, ruling out prostatitis or pyelonephritis. Acute prostatitis is identified by cystitis symptoms plus fever or sepsis, with imaging reserved for complications. Acute pyelonephritis is diagnosed by fever or sepsis, flank pain (spontaneous or on percussion), and positive urine culture; cystitis symptoms may be absent. Urine culture (thresholds: ≥10 ³  CFU/mL for bacteriuria, leukocyturia > 30 × 10 ³ /mL) remains the gold standard, while urine dipstick testing is not recommended due to low predictive value. Routine blood tests (inflammatory markers, PSA, or blood cultures) are unnecessary in outpatient management, even for febrile UTIs, unless acute kidney injury or complications are suspected. Pyelonephritis requires imaging (urgent in cases of sepsis or obstruction) to assess for uropathy, and epididymo-orchitis mandates STI screening.