The investigation of gross anatomical features of the gastro - intestinal tract (GIT) of the guinea pig (Cavia porcellus, Linnaeu-1758) was carried out. The aim of the study was to describe the gross anatomical anatomical features of the gastro - intestinal tract (GIT) of the guinea pig (Cavia porcellus, Linnaeus-1758). Fifteen healthy adult guinea pigs of both sexes were purchased from Samaru market in Zaria. The animals were anaesthetized and sacrificed, with the oesophagus, tongue, stomach, small and large intestines, liver, and gall bladder dissected. The tissue samples were immediately fixed by complete immersion in 10 % normal formalin, labeled and fixed. The various segments of the GIT were weighed, measured and photographs were taken. The results of the morphologic studies showed that the oesophagus was a direct con- tinuation of the pharynx, extending from the pharynx to the cardia of thestomach. The oesophagus lay dorsal to the trachea throughout its length until it entered the stomach. The stomach showed three regions, namely; cardia, fundus and pylorus, while the small in- testine showed also three regions, namely; the duodenum, the jejunum and the ileum. The large intestine had three distinct regions; the caecum, the colon and the rectum. The liver was divided into four lobes, namely: the right, the left, the intermediate and the ac- cessory lobes. The gall bladder was observed as a sac-like structure, with a light yellowish green colouration. The tongue was observed as a mass of striated muscle fibers covered by a mucous membrane. This work concluded that the gastrointestinal tract of guinea pig was similar to those of other ro- dents.