<b>Background and Objective:</b> Basil (<i>Ocimum basilicum</i> L.), an aromatic herb, is considered one of the most important crops with essential oils as well as other bioactive compounds. Basil leaves have tremendous pharmaceutical benefits and are used for foods. Slow-release fertilizers have been developed to optimize the fertilization of crops. This work aims to discover the effect of NPK Slow-Release Fertilizer Coated by Starch (NPK-SRFS) at different rates on growth, yield and essential oil components of basil grown on the field in Northern Vietnam. <b>Materials and Methods:</b> Basil seedlings, sown from seeds, were used as plant materials. NPK-SRFS was stocked in the Faculty of Chemistry, Hanoi Pedagogical University 2. The experiments were designed in a fully randomized block model, consisting of four treatments with different rates of NPK-SRFS. Each treatment had three replicates with an area of 8 m<sup>2</sup>. Duncan's Multiple Range Test was being used for statistical analysis (p = 0.05). <b>Results:</b> All 3 NPK-SRFS treatments significantly increased the number of buds and leaves per plant compared to the control. However, NPK-SRFS at different rates affected diversely plant height and leaf area of the basil. F5.0 and F10 treatments accelerated chlorophyll content as well as Fv/Fm value in comparison with none NPK-SRFS treatment. The application of NPK-SRFS at different rates caused slightly different changes in basil essential oil composition, especially the content of Methyl Chavicol, the most abundant oxygenated monoterpene and α-trans-Bergamotene, the most abundant sesquiterpene hydrocarbon. <b>Conclusion:</b> The present study provides further insight into the influence of NPK-SRFS on the growth, yield and essential oil components of basil.
Keywords: Basil (Ocimum basilicum); NPK-SRFS; essential oil composition; growth; yield.