Campomanesia rufa (O. Berg) Nied. is a native Cerrado species that presents great edible potential. However, it is a species “in danger of extinction” as recommended by the International Union for the Conservation of Nature (IUCN). No technical and scientific information about the species exists, thus demonstrating the importance of its research. The present work aimed at the physical and chemical characterization of immature and mature C. rufa fruits. The fruits showed a change in coloration from green (b * = 25.11, h = 122.43) to yellowish-green (b * = 34.26, h = 115.73), an increase in mass (6.54 g to 10.88 g), diameter (23.76 mm to 28.03 mm) and soluble solids (8.00 to 10.80%). The fruits presented high levels of total (1246.35 mg 100 g–1) and soluble pectin (195.93 mg 100 g–1), high water content (78.86 g 100 g–1), low pH value (3.40), and high citric acid content (1.2%). However, the fruits had low protein (0.81 g 100 g–1), lipid contents, and low caloric values (64.76 kcal 100 g–1). The fruits presented significant values of carotenoids, phenolic compounds (312.47 mg 100 g–1), vitamin C (263.60 mg 100 g–1) as well as good in vitro antioxidant activity (1862.81 µM g–1). The results obtained indicate that C. rufa fruits showed a similar composition to the fruits of other Campomanesia species, and their biological properties should be investigated additionally under in vivo conditions.