Ibuprofen is one of the pharmaceutical drugs that can be obtained over the counter in the Philippines. It is widely used for easing inflammation and pain. The Pasig River situated in a highly industrialized and urbanized area in the Philippines was studied. This is in order to know if Ibuprofen can be detected in this natural aqueous milieu using in-situ passive probe (Polar Organic Chemical Integrative Sampler or POCIS). This river is facing a lot of challenges with regard to the sewage systems and waste water treatments. This study shows the occurrence of the Ibuprofen in the important river of the capital of the country. Despite, different physico-chemical conditions of the Pasig River, Ibuprofen was still present. Compared to the concentrations found in the literatures, for a river, the concentration presented is high. Ibuprofen as an emerging pollutant can pose significant environmental concerns in terms its persistence and exposure of the microorganisms in this aquatic system. Concerns on human health can be raised as well as this river serves as an important source of water for daily use for those who does not have direct access to the local water service.