Severe leptospirosis (Weil Syndrome) was diagnosed in an otherwise healthy environmental worker in Baltimore alleys in late November 2010. He developed multiple organ failure but responded to antibiotic therapy and experienced a full recovery within 4 weeks. His diagnosis was confirmed by a rise in indirect hemagglutinin titer (acute 0, convalescent 400). The subject had close contact with Baltimore alley rats; a similar epidemiologic exposure and location reported in an outbreak 15 years ago.