In the case reported, M. fortuitum was sensitive in vitro to amikacin, erythromycin, tobramycin, and ciprofloxacin. Because the patient did not respond to long-term therapy with amikacin and erythromycin, an experimental antibiotic, ciprofloxacin, was tried. Only after extensive surgical debridement and 2 1/2 months of oral ciprofloxacin therapy was the infection eradicated and wound healing obtained. The authors conclude that a wound that has reopened, but remains indolent, exudes a clear, serous drainage and responds poorly to antibiotics should suggest a possible mycobacterial infection. Combination antibiotic therapy is recommended because of the high rate of relapse and development of resistance to drugs. Extensive surgical debridement of all infected tissue remains the primary treatment. The therapeutic value of ciprofloxacin and other newer antibiotics in the treatment of mycobacterial infection is promising.