The objective of this study was to extract poly(3-hydroxybutyrate) (PHB) from the microalgal biomass of Spirulina LEB 18 for the development of nanofibers by electrospinning method. Different extraction methods were tested. The maximum yield obtained was 30.1 +/- 2%. It was possible to produce nanofibers with diameters between 826 +/- 188 nm and 1,675 +/- 194 nm. An increase in the nanofiber diameter occurred when a flow rate of 4.8 mu L min(-1) and a capillary diameter of 0.90 mm were used. The nanofibers produced had up to 34.4% of biomass additives, i.e., non-PHB materials. This can be advantageous, because it enables the conservation of microalgal biomass compounds with bioactive functions.