Several factors have the potential to influence microalgae growth. In the present study, nitrogen concentration and light intensity were evaluated in order to obtain high biomass production and high phycoerythrin accumulation from Porphyridium purpureum. The range of nitrogen concentrations evaluated in the culture medium was 0.075–0.450 g L⁻¹ and light intensities ranged between 30 and 100 μmol m⁻² s⁻¹. Surprisingly, low nitrogen concentration and high light intensity resulted in high biomass yield and phycoerythrin accumulation. Thus, the best biomass productivity (0.386 g L⁻¹ d⁻¹) and biomass yield (5.403 g L⁻¹) were achieved with NaNO₃ at 0.075 g L⁻¹ and 100 μmol m⁻² s⁻¹. In addition, phycoerythrin production was improved to obtain a concentration of 14.66 mg L⁻¹ (2.71 mg g⁻¹ of phycoerythrin over dry weight). The results of the present study indicate that it is possible to significantly improve biomass and pigment production in Porphyridium purpureum by limiting nitrogen concentration and light intensity.