Antibiotics and antidepressants are among the most successful drugs used for human therapy. Their concentration in influent on WWTP is relative high and there can be removed by biodegradation or sorption. The aim of this study was to define the amounts of sorbed pharmaceuticals on digested sludge from WWTP Bratislava – Petržalka. The amounts of sorbed pharmaceuticals were calculated from knowing partition coefficients for selected pharmaceuticals and from analytically measured pharmaceutical's concentrations in sludge liquor. From this calculation were estimated the one-year sorbed amount of pharmaceutical onto sludge from wastewater treatment plant Petržalka (26,066 g/y for ciprofloxacin, 756 g/y for azithromycin, 647 g/y for clarithromycin, 445 g/y for venlafaxine and 148 g/y for citalopram).