An integrated circuit (IC) bipolar semiconductor photodiode array (PDA) microchip system coupled with light emitting diodes (LEDs) was used for rapid, automated cell viability measurements and high-throughput drug efficacy monitoring. Using the absorption property of trypan blue dye against the red light emitted by LEDs, we determined the effect of three anticancer drugs, viz., camptothecin (CAM), sodium salicylate (Na-Sal) and naringenin (Nar) on the cell viability of human promyelocytic leukemia cells (HL-60) and human embryonic kidney cells (HEK-293). Cell viabilities were measured based on the relative reduction in the photo responses of the photodiodes, covered with known concentration of trypan blue-stained cells. The developed method offers greater sensitivity and hence an excellent estimation of cell viability, but without all the hassle of conventional methods. Flow cytometric measurement and confocal microscopy were applied as complementary techniques for further validation of the results. The work presented here has important implications with regard to high-throughput measurement of optimal concentrations of different drugs against different cell lines in vitro.