The banana is among the most economically important crops for tropical and subtropical countries, where they have currently having great use in craft production, but it has been studied by many researchers to turn it into a high quality material for engineering. The extraction of the fibers of the banana pseudostem was done manually and without any chemical treatment. The fibers used in this study were drawn from the middle region of the pseudostem (trunk) of São-Tomé banana. They were characterized for their tensile strength, diameter, density and moisture content. The materials used for manufacture of polymeric composites were banana fibers, manually extracted from the pseudostem of São-Tomé banana (Musa sapientum, Musaceae), and an array of resin tereftálica unsaturated polyester and pre-accelerated chosen from the proportions of a 0.33% (v / v) 1.66% (v / v) 3.33% (v / v) and 5% (v / v) which was initially studied. In the manufacture of composite was used resin in combination with banana fibers with a length of 5 mm and mass fraction of 4.41% 5.41% and 6.41%. The specimens were fabricated by molding using silicone molds manual without release agent and without pressure. It's obtained the results of tensile strength and specific mass, of banana fiber (middle region), respectively, 1387 MPa and 1.56 g/cm3. The pure matrix with less curing agent, 0.33% (v / v) showed the best performance among the tested compositions, based on this, this proportion will be used for the production of other composites and as a standard for comparison among all series manufactured. The tensile strength of composites banana 5 mm with mass fraction of 4.41% was 26.60 MPa, for composites with mass fraction of 5.41% was 30.78 MPa, and for the mass fraction of composites 6.41% was 25.80 MPa.