One RP-HPLC and two chemometric assisted UV spectrophotometric methods were developed and validated for the simultaneous in vitro analysis of Atrovastatin calcium (ATV), Ezetimibe (EZET) and Fenofibrate (FEN) in their pharmaceutical preparation and ternary mixtures. The chromatographic separation was achieved on a reversed-phase, Hypersil BDS C8 column (250X4.6 mm i.d, 5 particle size) with a mobile phase consisting of methanol and 0.05M phosphate buffer (pH-6.3 adjusted with sodium hydroxide) in the ratio of (85:15)% v/v. The total run time was 7 min. Quantitation was achieved with UV detection at 248nm based on peak area. Linearity was observed over concentration range of 5 - 12μg mL-1 for ATV and EZET and 80 - 192 μg mL-1 for FEN. The two chemometric methods applied were inverse least square (ILS) and classical least square (CLS). These approaches were successfully applied to quantify each drug in their mixture using the information included in the UV absorption spectra of appropriate solutions in the wavelength range 220-310nm with the intervals of 5nm (Δλ = 5nm) at 19 wavelength points. For the chemometric calibration, 18 ternary solutions were prepared as training set and 10 ternary solutions were prepared as validation set. The developed methods were successfully applied for laboratory prepared mixtures as well as commercial tablet formulation for ATV, EZET and FEN concentration. The results obtained for pharmaceutical formulation by ILS and CLS methods were compared with isocratic HPLC method and a good agreement was found.