The carotenogenesis in Haematococcus lacustris, accompanying by encystment starting from green motile cells to aplanospores, is suggested mediating by reactive oxygen species (ROS). Our previous study showed that isobutyl-cyanoacrylate nanoparticles (IBCA- NPs) induced the cell mortality, preceding by intracellular ROS accumulation, in most of Volvocales species but not H. lacustris. This study aimed to investigate the effect of IBCA- NPs exposure to H. lacustris on carotenogenesis. The cells were cultured on C medium then exposed to 100 mg centerdot L−1 -1 of 180 nm of IBCA-NPs for the 14 days. The accumulation of astaxanthin was started after four days of IBCA-NPs exposure. The ratio of intermediate cells reached to 46% after 14 days of IBCA-NPs exposure, while the ratio of intermediate cells of untreated culture was only 11%. The results suggested that the addition of nanoparticles could enhance the production of astaxanthin. Further studies are required to investigate the correlation between nanoparticle exposure and ROS generation that leads to the biosynthesis of astaxanthin. The condition of cell growth and the addition of nanoparticles shall be optimized to increase the production of ketocarotenoid and to minimalize the negative effect of longer exposure time of IBCA-NP that could lead the cell mortality.