OBJECTIVE To study the relative bioequivalence of two sorts of domestic roxithromycin tablets. METHODS The randomized and crossover study was conducted in 18 healthy volunteers. After a single dose of the drugs given, their plasma drug concentration was determined by microbioassay. RESULTS Both the two sorts of domestic roxithromycin tablets were fitted to one compartment model. The main pharmacokinetic parameters of the tested and reference roxithromycin were as follows: C_ max (10.869?2.671) ?g/ml and (11.250?3.097)?g/ml; T_ max (1.7?0.8)h and (1.6?0.8) h; t_ 1/2 (13.407?2.391)h and (12.496?2.231) h; AUC_ 0-tn (127.097?32.971)?g?ml~ -1 ?h and (134.429?35.783) ?g?ml~ -1 ?h;AUC_ 0-∞ (136.556?33.958)?g?ml~ -1 ?h and (143.483? 38.052 ) ?g?ml~ -1? h; F_ 0-tn and F_ 0-∞ were (95.79?17.46)% and (96.58?16.66)%, respectively. CONCLUSIONS The results of analysis showed that the tested and reference formulations are bioequivalent.