This document summarizes a study that investigated heat transfer in a plate heat exchanger using water-based TiO2 nanofluids. Two different weight fractions (0.1% and 0.5%) of TiO2 nanofluids were prepared and their heat transfer performance was experimentally tested in the plate heat exchanger. The results showed that the 0.5% nanofluid provided significant enhancement of the overall heat transfer coefficient at higher Reynolds numbers compared to water, while the 0.1% nanofluid showed a decrease compared to water.