In this study characterization and biological treat ability of tablet production wastewaters of a pharmaceutical industry were assessed. Source-based wastewater characterization of tablet, pastille, effervescent tablets and chewing tablet productions indicated variable strength of wastewaters with COD values between 1030 and 6700 mg/L. Biological treatability studies conducted on these wastewaters showed that the wastewater having BOD/COD ratios above 0.4 could be effectively treated using activated sludge process at 0.21-0.25 g COD/(g VSS d) organic loading. One of the tablet production wastewaters was found to be practically non-biodegradable. Ozonation of this wastewater yielded a limited increase in biodegradability. 60% COD removal could be obtained by biological treatability experiments at organic loadings of 0.06 to 0.1 g COD/(g VSS d) using composite samples prepared as a mixture of ozonized and non-ozonized tablet wastewaters.