This article gives fiber dimensions and derived values obtained for 23 bamboo species, besides similar data for 4 species previously reported by the authors. The average fiber dimensions found for the 27 bamboo species ranged as follows (in milimeters): length, from 1.325 for Bambusa beecheyana to 2.744 for Gigantcchloa apus; width, from 0.00839 for Pleioblastus simoni to 0.02090 for Bambusa beecheyana. The length diameter ratio ranged from 63:1 to 264:1, the shortest ratio being that of Bambusa beecheyana and the highest one of Bambusa vulgaris. The coefficient of variation for fiber length ranged from 26.50% to 42.32% and for fiber width from 17.80% to 60.09%. Considering the ease of bamboo cultivation, the high and rapid production per area, and the quality of the fiber, bamboos areunquestionably the most promising source for cellulose production in the tropical and subtropical regions. As in many other countries where bamboo is being used on a large scale for the pulp and paper industry, it seems likely that in Brazil this plant as a commercial crop will be, in very near future, an important source of long-fibered pulp for blending with short-fibered pulps in papermaking.