Coretop sediment samples covering water depth from 247 to 1474 m in the Northwestern Indian Ocean were analyzed. 6 species of Uvigerina among 77 species and 11 species-complexes were found in all 26 samples. They are Uvigerina auberiana d’Orbigny, Uvigerina hispida Schwa-ger, Uvigerina peregrina Cushman, Uvigerina proboscidea Schwager, Uvigerina spinicostata Cushman and Jarvis, and Uvigerina sp. Characteristics of Uvigerina are (1) high abundance due to rich food supply and less competitors; (2) low diversity because only those eurytopic / opportunistic forms can survive environment of low dissolved oxygen value; (3) various test shapes and ornamentations which are controlled by respiration or gas exchange of the cell; and (4) abundance of Uvigerina is well related with environmental factors such as water depth, oxygen content and productivityor food supply. These Uvigerina species can be used as pa-leo-environmental proxy of low oxygen and rich organic matter supply related to high-surface productivity Six species of Uvigerina among 77 species and 11 species-complexes were found in all 26 samples. They are Uvigerina auberiana d’Orbigny, Uvigerina hispida Schwa- ger, Uvigerina peregrina Cushman, Uvigerina proboscidea Schwager, Uvigerina spinicostata Cushman and Jarvis, and Uvigerina sp. Characteristics of Uvigerina are (1) high abundance due to rich food supply and less competitors; (2) low diversity because only those eurytopic / opportunistic forms can survive environment of low dissolved oxygen value; (3) various test shapes and ornamentations which are controlled by respiration or gas exchange of the cell; and (4) abundance of Uvigerina is well related with environmental factors such as water depth, oxygen content and productivityor food supply. These Uvigerina species can be used as pa-leo-environmental proxy of low oxygen and rich organic matter supply related to high-su rface productivity