The efficacy of levofloxacin and dirithromycin, alone and in combination with rifampicin in the treatment of experimental brucellosis was investigated. Seventy adult white male mice were infected intraperitoneally with Brucella abortus S544 standard strain. Four of the animals were sacrificed on the 21st day of inoculation for infection control. The remaining 66 mice were randomised into treatment and control groups. Following 14 days of treatment the animals were sacrificed and spleen cultures were made. The cure rates were 36.4% for levofloxacin, 27.3% for dirithromycin, 72.7% for rifampicin, 72.7% for levofloxacin + rifampicin and 81.8% for dirithromycin + rifampicin. The results of this study indicate that levofloxacin and dirithromycin are ineffective in the treatment of experimental murine brucellosis as monotherapy or in combination with rifampicin.