Spinner dolphins (Stenella longirostris) were surveyed and photographed during the Spring/Summer of 2004-2007 in the Southern Tañon Strait region of the Philippines. Over 17,000 images of dorsal fins were taken during the study period for photoidentification purposes. The study area (approximately 100 Km2) is a popular site for cetacean-watching and more recently underwent oil exploration and drilling. A photographic database of 329 unique spinner dolphin dorsal fins was produced, and used to assess abundance and life history characteristics using DARWIN software. An overall abundance estimate (2004-2007) of 1118 individuals (990-1246 with a 95% confidence interval) was obtained using the POPAN feature of MARK software. These mark-recapture results reveal that approximately 28% (n= 92) of the identified individuals (n= 329) were present in the study area in at least two of the four study years. This information is necessary to gain a better understanding of the ecology and life history characteristics of small cetaceans in the Tafton Strait, and in the development of conservation, education, and habitat protection programs designed to protect these cetaceans from human impacts. This project is part of a long-term ongoing study of the small cetaceans in the Southern Tañon Strait.