Swamp buffaloes (Bubalus bubalis) have been adapted and grown in swampland of South Kalimantan, Indonesia. They have been success to survive in swampland with extreme condition where the feed supply is low on quantity and quality. The ability of swamp buffaloes for adaptation to swampland was suggested to be supported by digestive efficiency. The ability of digestive efficiency on swamp buffalo is often closely related to large rumen volume, slow rumen motility, high cellulolytic activity of microbial population, and slow rate of digestion passage through the reticulo-rumen (Falvey and Chantalakhana, 1999). The efficiency of digestive system in a species maybe also has correlation to the characteristic morphological of stomach. Perez-Barberia, et al. (2004) stated that digestion efficiency can be achieved via stomach adaptation and that this varies between species. To our knowledge, there is no available information concerning morphological adaptation of the stomach of swamp buffaloes. This study was very important to obtain a better understanding of the digestive efficiency of the swamp buffalo by examining the morphology of the stomach of the swamp buffalo with special emphasize on its macroscopic and surface structures.This study utilized 6 stomachs from 2.5-3 years old healthy male swamp buffaloes. Samples were obtained at the local slaughterhouse, South Kalimantan, Indonesia. The stomach was removed after sectioning the esophagus just cranial to the cardia, and pylorus adjacent to the duodenum. The gross morphology and the interior features were observed and certain portions were measured. Weight of organ was measured by weighing it after it had been opened and contents rinsed with tap water and dried with paper towels. Anatomical measurement was done by spreading the organ. The longest part was measured as length and the widest part was measured as width with soft measuring tape (Perez and Rodolfo, 2012). Pictures were taken with a digital camera.Stomach filled more less ¾ part of abdomen ( Figure 1A). The stomach of the swamp Buffalo composed of the four classic compartments of the ruminants ( Figure 1B). The weight mean of the empty rumen was 6370 g. The length mean of the rumen was 108 cm and the width mean was 70 cm. The ruminal papillae were distributed unequally in the rumen. It was more abundant within the ventral rumen than dorsal rumen, whereas the ruminal pillars had no papillae (Figure 2).The shape of ruminal papillae swamp buffalo had variation from the leaf-like, needle-like, end expansion, top branching, and lateral branching (Figure 3). The maximum length of ruminal papillae was 2.75 cm. The various forms of papillae arise from epithelium expansion on the one hand and from muscular contraction on the other hand (Wardrop, 1961). According to McGavin and Morrill (1976), the branching of the papillae was an example of hyperplasia to increase surface area. Papillae increase the surface area for absorption and thus play an important role in absorptive capacity (Swan and Groenewald, 2000). The enl...