A reversed-phase ion-pairing high-performance liquid chromatographic procedure with refractive index or UV 214 nm detection was developed for the separation of clindamycin, clindamycin B, and 7-epiclindamycin. The chromatographic retention behavior of these compounds on an octadecylsilane column was investigated as a function of pairing-ion, mobile phase composition, and pH. The method was applied to the determination of clindamycin in bulk drug and in a number of pharmaceutical formulations. The relative standard deviations for all assays was in the 0.5-2% range.