Teesta (or Tista) River is one of the major rivers in the North West region of Bangladesh.Originated from the foothills of the Himalayas in Sikkim, the river passes through the states of Sikkim and West Bengal in India before finally entering into Bangladesh at Dimla in Nilphamari district. The river finally merges with the mighty Jamuna river at Chilmari in Gaibandha district. On its way, the river passes through five districts of Bangladesh. These are: Nilphamari, Lalmonirhat, Rangpur, Kurigram and Gaibandha. The ecosystem of the districts of Kurigram and Gaibandha is also influenced by the Jamuna River and its tributaries while the other three districts are mainly dependent on the Teesta flow.The annual flow of water through Teesta varies dramatically between wet and dry seasons. According to one estimate Teesta supplies nearly 4494 cumec1 of water in summer while the minimum is only 8 cumec measured at Dalia, Nilphamari (Islam, 2009). The dry flow of the river is highly controlled for hydro and for irrigation projects both in India and in Bangladesh. Reduction of dry season flow of Teesta has significant consequences on its ecosystem services. It is through this process, the mighty Teesta has been tamed as it lost its might and its flow has reduced to only a few cumecs in dry periods.Teesta travelled through a diverse ecosystem. It originated from several Himalayan glaciers in Sikkim and passes through the tundra forests and through mountainous terrains covered with dense natural forests. From a height of 4000 meters up, Teesta sharply descends into the plains near West Bengal. The lower Teesta (from West Bengal onwards) River flows through dense tropical forests and through the floodplains. In the floodplains of Bangladesh, Teesta provides water for agriculture, livelihood nearly 2.1 million people engaged in agriculture and capture fisheries and the major navigation source for remote villages and riverine islands.Over time, a number of dams and barrages have been built on the river starting from its source in Sikkim to the last barrage at Dalia in Bangladesh. None of these barrages were built to control the flash floods, rather these were built to provide water for agricultural land. As water flow is diverted by both India and Bangladesh to produce electricity and/or to irrigate agricultural land it has impacted the flow of water in the downstream regions (after each diversion) in the dry season. Based on the theoretical foundations embedded in production and cost functions in Economics and using revealed preference theories, the study has been able to estimate provisional services of water lost from Teesta River due to upstream withdrawal. The results are valid for both Bangladesh and India. In terms loss in agricultural production (crops and fisheries) the value per acre per annum is 3106 taka or 39 US dollars. This is equivalent of 3.22 taka per year per acre per cumec of water. In terms of loss in fisheries, it is 599 taka per fisher per year or 7.68$. This is equivalent of 0.62 taka per year per cumec of water.Furthermore, upstream water withdrawal does not always lead to losses in ecosystem services of a river, it only happens when the river is tamed or choked due to heavy withdrawal or diversion of water. This study has observed that people in downstream areas are living in a water scarce regime. The impact of which when translated into monetary terms is equivalent of 1,953.91 million taka or 25 million US$ per year. This is equivalent of nearly 2.03 million taka (or 25,970 US$) per cumec of water per year. Moreover, this loss is only in Bangladesh.