A  spectrophotometric  and  a  spectrofluorimetric  procedure  for  the  quantitative  determination  of  four  macrolide  antibiotics  (erythromycin,  josamycin, roxithromycin  and  spiramycin)  are  described.  Both  methods  are based on the reaction of the antibiotics with phosphoric acid followed either by measuring the absorbance at 482 nm or the fluorescence at 468 and 505 nm for excitation and emission wavelengths, respectively. The different experimental conditions have been optimized. Beer’s law was valid over the concentration ranges 7.5-60. µg ml^-1 and 1.0 – 12.0 µg ml^-1 for spectrophotometric and fluorimetric methods, respectively. The detection limits ranged from 0.16-1.3 µg ml^-1 for both methods. The two procedures have been applied to the assay of these antibiotics in their commercial tablets. The results showed insignificant difference when compared with those obtained from reference methods as revealed by statistical analysis using t- and F-tests.