The study estimates temporal and regional variations of nitrogen and protein content of the green algae Ulva fasciata and the red Corallina officinalis collected at three sites of the different entities along the Alexandria coast. The heterogeneity in environmental conditions contributes significantly on the variation of the algal nitrogen and protein contents. However, the varied storage of nitrogen by the algae cannot be directly linked to the ambient dissolved inorganic nitrogen concentrations. Ulva fasciata can accumulate higher concentrations than Corallina officinalis. The study suggests a new nitrogen-protein conversion factor to be applied for each species. A comparison with other published data is discussed.