Lipids are essential components in all living cells with diverse roles in membrane structure maintenance, signaling, energy storage and many other fundamental cellular processes. Toxoplasma gondii, a ubiquitous zoonotic parasite infecting one third of the world"s human population, has complex pathways to synthesize variety of lipids. The enzymes involved in lipid synthesis are localized in many different organelles that include the apicoplast, endoplasmic reticulum, mitochondrion, Golgi, and nucleus. The compartmentalization of the lipid synthesis pathways requires the transport of lipid precursors among different organelles and the delivery of the final lipid products to the correct destination. However, the underlying mechanisms are largely unknown. In cells, lipid transport may occur mainly through vesicular and non-vesicular mechanisms. Non-vesicular lipid transport requires lipid transfer proteins. Oxysterol-binding proteins (OSBPs) and their related proteins (ORPs) form a large family of lipid binding/transfer proteins. Some of the OSBP and ORP proteins have important roles in mobilizing lipids between different organelles. In this study, we have identified two OSBP proteins in T. gondii. Using genetic and cell biology approaches, we found that one of the OSBP protein (OSBP1) is critical for the asexual reproduction of tachyzoites while the other one is dispensable. Further analyses showed that OSBP1 is located at the membrane contact sites between the endoplasmic reticulum and the Golgi, and it played important roles in the synthesis and proper cellular distribution of a number of phospholipids, including the abundant phosphatidylinositol.