The present study was carried out to evaluate the effect of dietary Spirulina platensis and Chlorella marina supplementation on growth performance, feed efficiency, survival (%), apparent digestibility coefficients (ADCs) and economics analysis of European seabass, Dicentrarchus labrax, post larvae during 60 -120 days of weaning period in hatcheries.. A total of 180 seabass post larvae with an average body weight of 0.20 ± 0.01 g were divided in the three experimental treatments (three replicates each). The experiment was conducted for 60 days. Three iso-nitrogenous (53.64% crude protein) and iso-caloric (15.67MJ/kg, DM) weaning diets were formulated. The control diet had no Spirulina platensis and Chlorella marina added. Diets 2 and 3 each were formulated to contain 5% S. platensis and 5% C. marina, respectively. The final weight (FW), average daily gain (ADG), specific growth rate (SGR) , survival (S%) and proximate body composition of D. labrax post larvae were significantly (P £ 0.05)improved in experimental diets supplied with Spirulina platensis and Chlorella marina microalgae compared to the control group. The same trend was recorded for best feed conversion ratio (FCR), protein efficiency ratio (PER), protein productive value (PPV), energy retention (ER) and energy utilization (EU). The higher significant apparent digestibility coefficients values of dietary protein and lipid were recorded for fish fed S. platensis than other treatments.  No statistical difference (P ≥ 0.05) was observed for the influence of dietary S. platensis and C. marina microalgae on whole body proximate analysis of D. labrax post larvae. The change in incidence cost were highly significant (P<0.05) for fish fed control diet compared with diets containing S. platensis and C. marina tested algae. The results of present study suggested that European seabass, D. labrax, post larvae fed diets containing 50 g/kg of Spirulina platensis and Chlorella marina for 60 days had promote and enhanced growth performance, diet utilization efficiency and dietary nutrients digestibility coefficients.