The use of natural fibers as reinforcement in composites has been developed by researchers because of their eco-friendly, renewable, and potential replacement for synthetic fibers. Sumberejo kenaf fiber is one of the abundant natural fibers in Indonesia. The purpose of this study was to obtain the mechanical properties of Sumberejo kenaf fiber/ epoxy composites. The alkaline-treated fibers were arranged in 0°/0°/0°/0° and 0°/90°/0°/90° orientations. Composites with 40 wt% fiber content were fabricated using hand lay-up and followed by vacuum bagging method. The results showed that the tensile strength and flexural strength of Sumberejo kenaf fiber/ epoxy composites with 0°/0°/0°/0° fiber orientation were 11.73% and 37.71% higher than the composites with 0°/90°/0°/90° fiber orientation with the values of (91.18±9.85) MPa and (116.57±7.91) MPa, respectively. Scanning Electron Microscope (SEM) observations on the failure surface of the composites showed that the composites with 0°/0°/0°/0° fiber orientation had better fiber and matrix adhesion and lower voids content than the composites with 0°/90°/0°/90° fiber orientation. Referring to Indonesian National Standard 01-4449-2006 for composite fiberboard, Sumberejo kenaf fiber/ epoxy composites were categorized as a T2 45 type high-density fiberboard.