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Between June 2004 and April 2006, 381 hours of dolphin surveys were undertaken in the waters off the village of Bayahibe and Parque Nacional del Este on the southeastern coast of the Dominican Republic. This was the first time that dedicated dolphin surveys have been conducted in this area. In the Parque Nacional del Este, six species of cetaceans were identified: bottlenose dolphin (Tursiops truncatus), Atlantic spotted dolphin (Stenella frontalis), Pan-tropical spotted dolphin (Stenella attenuata), humpback whale (Megaptera novaeangliae), short-finned pilot whale (Globicephala macrorhynchus) and sperm whale (Physeter macrocephalus). The two predominant species were the bottlenose dolphins and Atlantic spotted dolphins, which appear to be resident year round in the area. Bottlenose dolphin group sizes ranged from 8 to 33 (mean 14.11, SD 8.05) and Atlantic spotted dolphin group sizes from 8 to 36 (mean 17.33, SD 12.12). Calves of both species were seen throughout the year, indicating that there is no particular season for reproduction. Mixed groups containing both species were also recorded. Animals with dorsal fin injuries suggestive of propeller injuries were observed. Humpback whales, with calves, also were recorded in the area between January and March. In Samana Bay, in the northern Dominican Republic, opportunistic surveys, using whalewatching vessels as platforms of opportunity, were conducted. Both bottlenose dolphins and Atlantic spotted dolphins were again identified and whalewatching operators reported a sighting of short-finned pilot whales. Bottlenose dolphin group sizes ranged from 1-18 (mean 5.16, SD 6.67) and from 2-20 for Atlantic spotted dolphins (mean 12.5, SD 8.43). Dolphins were observed interacting with humpback whales. Further research in the Dominican Republic will improve our understanding of the social structure and ecology of these populations and will allow us to evaluate anthropogenic threats, but coastal development and tourism are increasing rapidly and may pose risks to coastal cetacean populations in the Dominican Republic.