New, simple, cost effective, accurate and reproducible UV-spectrophotometric methods are developed and validated for the estimation of quetiapine fumarate in bulk drug and tablet formulation. Quetiapine was estimated at 239 nm in 0.1N hydrochloric acid (pH 1.2) and at 250 nm in ethanol. Beer’s law was obeyed in the concentration range of 1–12 9gmL-1 (r2 = 0.9999) in hydrochloric acid and 1–14 9gmL-1 (r2 = 0.9998) in the ethanol. The apparent molar absorptivity and Sandell’s sensitivity coefficient were found to be 4.63×104 L mol−1 cm−1 and 9.5 ng cm−2/0.001A in hydrochloric acid; and 4.08 ×10 4 L mol−1 cm−1 and 10.8 mg cm−2/0.001A in ethanol, respectively indicating the high sensitivity of the proposed methods. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.0402, 0.1217 9gmL -1 in hydrochloric acid and 0.0384, 0.1163 9gmL -1 in ethanol, respectively. The proposed methods were successfully applied for the determination of quetiapine in pharmaceutical formulation (tablets). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation < 2%), while being simple, cheap and less time consuming and hence, can be suitably applied for the estimation of quetiapine in its tablet dosage.