The phytoplankton composition was investigated on a cross-shore transect in the Northern Benguela upwelling system in August and September 2011. Micro- and nanorganisms were microscopically analysed and assigned to appropriate phytoplankton groups. The distribution of diatoms, dinoflagellates, coccolithophores and nanoflagellates along the transect was studied in order to reflect the phytoplankton succession. Typical phytoplankton communities indicating different stages of succession were found in relation to the distance to the coast and in relation to the aged upwelled water. Three succession stages could be well defined and verified by satellite data in the newly upwelled water, matured water and aged offshore water. The different stages were distinguished not only by the significant differences in the nutrient concentrations but also by the dominating species and phytoplankton life forms. A mixed population of dinoflagellates, coccolithophores and microflagellates were observed in the newly upwelled water. Small diatom cells (Cylindrotheca closterium) marked the transition to the matured water at about 40 km from the shore. A diatoms to dinoflagellates ratio up to 33 and biomasses up to 250 μgC l− 1 were characteristic for the matured stage, between 40 km and 250 km from the coast. As observed by satellite data, highly productive water bands intrude the water masses which also represent this stage. They were characterized by accumulated biomasses dominated by diatoms (Pseudo-nitzschia seriata group). Diatoms to dinoflagellates ratios less than 1 and maximum biomasses of 15 μgC l− 1 characterized the aged water at the later stage of succession. Abundances of dinoflagellates smaller than 10 μm increased just after the decline of the diatoms. Keywords: Northern Benguela, phytoplankton succession, species composition, upwelling, remote sensing, diatoms to dinoflagellates ratio.