This research is intended to expand information on fiber characteristics for better understanding their complexity and potential in industrial use. Tensile properties of four types of individual cellulosic fibers, bamboo, kenaf, Chinese fir, and ramie, were measured by a custom-designed microtensile tester. Load-displacement curves for most individual fibers were found to be linear until failure. Average values of at least 30 individual fibers of bamboo, kenaf, Chinese fir, and ramie were 1685, 983, 908, and 1001 MPa for tensile strength; 26, 19, 14, and 11 GPa for tensile modulus; and 7.1, 5.4, 8.3, and 8.9% for elongation at break, respectively. Cross-sectional areas of cell walls measured by confocal laser scanning microscopy were 117, 140, 217, and 337 mu m(2), respectively, an inverse relation with tensile modulus. Among the fibers, bamboo had the greatest tensile strength and modulus, whereas the other three did not have any statistical difference. Ramie had the largest elongation at break and the lowest modulus. Elongation at break of kenaf was significantly smaller than that of the other fibers. Fracture morphologies and load-displacement curves indicated these fibers were brittle materials. Tensile data can be used to screen fiber applications.