Chemical composition of eight Egyptian marine macroalgae, Ulva lactuca and Enteromorpha linza (Chlorophyceae); Dictyota dichotoma, Sargassum vulgare and Cystoseira spinosa (Phaeophyceae); Pterocladia capillacea, Corallina officinalis and Jania rubens (Rhodophyceae), was determined. Water content in all algae analyzed was high (<80.1%) especially in green algae. Ash content exhibits its highest values in the studied red algae. Total protein values varied within the different studied species, showing the highest value (19.7%) in the red alga Pterocladia capillacea. The two green algal species (U. lactuca and E. linza) showed the highest soluble carbohydrates content (28.4 and 33.4 %, respectively). Crude lipids values represented very low percentage of the chemical composition of the studied algal species. The highest caloric values were recorded for U. lactuca and E.linza. Values of different chemical constituents of the drift algae analyzed were comparable with those values recorded for attached algal specimens. The results of this work support utilization of marine macroalgae as untraditional natural source of protein and carbohydrates. Also, the richness in nutritional composition in drift algae and the ease with which they collected, make it preferable to use them rather than using the attached algae.