Abstract Two sensitive and selective methods were developed for the simultaneous determination of four commonly used non-steroidal anti-inflammatory drugs (NSAIDs), namely; paracetamol (PCM), diclofenac sodium (DCF), ibuprofen (IBP), and indomethacin (IND) in wastewater effluents. The first method used HPLC for the determination of the studied drugs using a mobile phase consisting of phosphate buffer (pH 3.0) and acetonitrile at a flow rate of 1 mL/min. in gradient elution mode and detection at 220 nm. The separation process was performed on BDS Hypersil Cyano column (250 x 4.6 mm, 5 μm). The second method was a TLC-densitometric one which was performed using n-Hexane: ethyl acetate: acetic acid in the ratio (6:3.

5:

0.5) as a developing system. The proposed chromatographic methods were successfully applied for the selective determination of the four studied drugs in simulated and real pharmaceutical wastewater samples after their solid-phase extraction