To determine the bioavailability of clindamycin from the microbiologically inactive clindamycin-2-palmitate and clindamycin-2-hexadecylcarbonate in man, a three-way crossover study was conducted with oral administration of the two esters and clindamycin hydrochloride. In each case, serum clindamycin bioactivity concentrations were fitted to a one-compartment open model with an initial lag time. Analysis of variance of measured quantities (serum concentrations and urinary excretion) and of derived pharmacokinetic parameters showed that for every comparison except maximum serum concentrations clindamycin-2-palmitate was not significantly different (at p=0.05) from clindamycin hydrochloride. Clindamycin-2-hexadecylcarbonate gave significantly different values from those for the hydrochloride in all cases except the rate constant and half-life for elimination from the serum. The palmitate was the superior ester and was bioequivalent to the hydrochloride in man.