A biopharmaceutics drug classification system for correlation between in vitro dissolution and in vivo bioavailability is proposed based on recognizing that drug dissolution and gastrointestinal permeability are the fundamental parameters controlling the rate and extent of drug absorption. The objective of this study was to assess whether in vitro dissolution profiles of immediate-release beta-blocker tablets can be correlated with intestinal membrane permeability and/or in vivo bioavailability In vitro dissolution of the beta-blocker tablets was examined using KP VII Apparatus II methods at various pH. Intestinal membrane permeability was determined in vitro using the diffusion chamber method. Bioavailablity parameters were cited from literatures. The dissolution profiles did not accurately represent the in vivo bioavailablity However there were good correlations between intestinal membrane permeability and log P (noctanol/buffer). The correlations obtained in this study indicated that in vitro diffusion chamber method could be used to predict intestinal absorption in vivo.